In an age of austerity and public service cuts, Britain's trade union leaders are playing a more central role than for many years. In the run-up to the TUC congress, we get to know them better. Portraits by Antonio Olmos

Len McCluskey, 61, general secretary, Unite

A former Liverpool dock worker, McCluskey leads Britain's biggest union, with 1.6 million members. He joined the union movement in 1968 and was elected to his current post almost a year ago. He has since been dubbed "Red Len" for his high-profile involvement in Unite's dispute with British Airways.

Is public sympathy for the unions decreasing?

When anything's reported, it's strikes and disruption, even though 90-odd per cent of the time we're involved with companies and organisations it's helping, adding value, and good relations increase productivity. But I think things are changing. There was that massive march on 26 March, tens of thousands of people who were not union members. More and more people who have no voice are starting to look to us as the only alternative to being ignored. But, also, we need to work increasingly to make ourselves more relevant to people's lives, particularly in the newer industries with less of a history of unionism.

Did the Blair years help or hinder?

The "I'm all right, Jack", "no such thing as society" concept started by Thatcherism was also cultivated under Blairism. The culture of collectivism, community spirit, has taken a battering for ages. Of course I voted Labour, though I was never a supporter of Blairism. They treated the union movement with disdain: happy to take our money but not to attempt to understand our values. Which are about collectivism, working for one another and with one another. Instead of worrying about the image of unions, people should simply come and join us.

You sound as if you're talking about Mr Cameron's 'big society'.

I do, don't I! And the thing is, we made exactly that point when it came out. We said, well Unite is the big society – 1.6 million members in every sector of the economy, trying to help each other.

But the vitriol directed, from all sides, at any strike action seems to be increasing exponentially.

When any service workers take action, innocent members of the public suffer. And nobody likes that. It would change if people realised, away from the tabloids, that nobody wants to go on strike, nobody wants to inconvenience people. I've been involved in a lot of actions and I have never yet met a worker who actually physically wants to strike, for goodness' sake.

Cameron or Clegg?

Very good question. Cameron – at least you know where you stand with him and the class he represents. Clegg I just think is a disgrace and is selling out the heritage of a very proud political party, which has always stood for fairness and on occasion has been far more radical than the Labour party. I'm not sure how he sleeps at night. I'm sure David Cameron sleeps far easier.

Do you sleep easily?

Absolutely. Mainly because I'm exhausted most of the time.

What drives you personally?

Child of the 60s, I suppose. I was infected by the concept of fairness, equality, justice – there was a kind of revolutionary period to all that we did and that's stayed with me. What I've learned is… if you can judge a person properly, you'll never be disappointed. It's only when you misjudge that you let yourself open to betrayal.

Which songs have meaning for you?

Back in the 60s, the anti-war songs. Everyone goes on about Bob Dylan, but Paul Simon's been a greater influence. There's a fabulous one called "The Side of a Hill". And his "Kathy's Song" is one of the best love songs ever. And "Somewhere Over the Rainbow" by Eva Cassidy; I used to sing that as a lullaby to my daughter and she now sings it, beautifully, to me.

Paul or John?

Oh God. It's the hardest thing you can ask a Liverpudlian. Both fabulous in their different ways. Oh God. John, I'd have to say. Just.

You were gracious enough to insist at the start that I call you not Mr McCluskey but Len. What about Sir Len?

No. You'll never get to the point where you have to call me that.

Christine Blower, general secretary, National Union of Teachers

'I believe Michael Gove's intentions are genuine. I just think he's wrong.' Photograph: Antonio Olmos for the Observer

Daughter of a former miner from the north-east, Blower was brought up in Kingston upon Thames and first taught (French) at Holland Park School in west London. She joined the NUT at the start of her career and became general secretary in 2009. She is a critic of SATs and withdrew one of her and her partner Dennis's two daughters from Key Stage 2 tests.

Is the public sympathetic to your aims?

They are when they're asked individually about it. It depends how one presents the role of the the union. Especially young people. It's safe to say there aren't a lot of positive demonstrations of trade unions in the media; it isn't surprising young people don't have a wholly positive image. But talk to them individually and they listen.

What drives you personally?

I am passionate about education and truly believe it is the way out of poverty and ignorance and liberating minds and making a better society. That ties with the trade union movement; they're the same values, seeking a society much more shot through with equity.

What do you think of the coalition?

We've got a government for which no one voted, so we've been getting some unfortunate outcomes. It's clearly better to have a government than not. Although they do seem to have managed rather well in Belgium, don't they? What we have been tremendously disappointed by is the headlong rush towards academy schools; we believe that local democratic accountability is the way to run an education service, not having 22,000 free-standing institutions.

What most worries your members?

The unfairness of Ofsted. The accountability measures give no picture of how hard and well a school works and how much effort is going in. I'm not a great fan of the all-must-have-prizes idea, but there have to be some fairnesses. Also, one of the things that develops young minds extraordinarily is grappling with questions to which which no one actually knows the answer.One of the difficulties is the pressure to teach what can be "measured", rather than what we value.

Where do you holiday?

My partner's Maltese and my children love to go to Malta. But this year I used my holiday to go to… well, a union conference.

How do you feel about being vilified during the recent pensions action? (She was described as a "hate-filled woman" under the heading "The Scargirls".)

I didn't recognise the caricature of myself in some sections of the media. But it's designed not just to upset me, but crucially to destabilise the members.

How do you get on with your opposite number, as it were?

I find Michael [Gove] charming and he's never been anything less than courteous to me. I believe his intentions are genuine entirely and would never accuse him of bad faith. I just think he's going utterly the wrong way about doing it.

Your desert island luxury?

It would be genuinely a luxury: a hypoallergenic pillow. No it's not the sexiest luxury of all time but, look, if you were on a desert island, wouldn't you just *love* to have something soft and safe to put your head down on?

Bob Crow, 50, general secretary, National Union of Rail, Maritime and Transport Workers

'The unions might have to cut their ties with Labour.' Photograph: Antonio Olmos for the Observer

Born in Shadwell, London, Crow has called himself a "communist stroke socialist". He got involved in union politics as an underground track repairer for London Transport and succeeded Jimmy Knapp as union head in 2002. He lives in a housing association property in Woodford, north-east London, with his partner, Nicola, and has two children, one from a previous marriage. He is a lifelong Millwall fan.

Are the public sympathetic?

They are, actually. The problem is that about 33 per cent of the workforce are now in a union, down from 67 per cent in 1977; most people aren't members. But once it's explained in a sensible manner what the movement is about – making sure you come back from work in one piece, decent pay and conditions, but also social justice – they do recognise our role. The hostile media are that way because they think there'll be infringements on their profit line; that's why media bosses have a go at unions. But people I speak to personally, they say, Good on you.

What drives you personally?

For the first time in 60 or 70 years, people are seeing their pay packets getting smaller, prices going up, and their job security completely disappearing. I think they might be starting to see what a trade union's for.

What do you think of the coalition government?

It's pretty clear what's happening in my view, which is that any time there's dirty work to be done, they send the Liberals in. They sent Vince Cable up to the GMB conference, for example; and they're taking all the flak. And again it's pretty clear to me what'll happen over the next 12 months or so, it'll get back to the polarisation between Labour and Tories again.

Do you still have faith in the Labour party?

Ed Miliband said he wouldn't go to the Durham miners' gala 'cos I was there! He went to the Murdochs' garden party but he wouldn't go to the Durham miners' gala. And the worst is that he told those teachers and civil servants that they should work on 30 June. When it comes to a strike, you're either on the side of the bosses or the side of the workers. There's no in-between.

Would you like the chance to run London Underground, rather than just represent the workers?

You couldn't do two jobs, not full time. I would like, however, an opportunity to sit on a board sometimes, not as a board member but just say four times a year or something, Network Rail or London Underground, and just give the view on how workers might be able to help run the system better. There's ideas that workers come up with every day that are never taken into account. There's no input, no process. You've got thousands of consultants for free here – workers who do the job every day. And passengers. They should talk to us more.

You are high-profile among union leaders. Do you get recognised?

Pretty much all the time. But I never get any aggravation, honestly. People come up and ask questions about the railway, and if can answer them I do.

Will unions exist in 100 years' time?

Labour is all over the shop because it wants to represent both big business and workers. You can't. It's got to make up its mind. Or the trade union movement has to cut ties with Labour and form a new party of labour. Yes, we might be approaching that time.

Mark Serwotka, 48, general secretary, Public and Commercial Services Union

'They're using the economic crisis to dismantle the welfare state.' Photograph: Antonio Olmos for the Observer

Serwotka spent the first six months of his life in a Catholic orphanage in Cardiff before being adopted by a Polish-British father and a Welsh mother. He joined the civil service at 16 as a benefits clerk, becoming a union member on his first day.

Is the public broadly sympathetic to your aims?

I think so, yes and recent opinion polls point in this direction. It's becoming increasingly clear, not just the scale of what the government intends to do to the public sector, but that they have no mandate for what they're doing.

Is this an historic moment in union history?

We are at a crossroads, absolutely. The stakes are incredibly high in respect of whether the unions can step up to the plate and be seen to be relevant. If we're not seen to be relevant, we may well see the union movement in steep decline. On the other hand, if we are seen to be relevant, we'll grow significantly in terms of both numbers and influence.

What do you think of the coalition?

There's no question that they're doing this from an ideological perspective. They're seizing on the economic crisis to dismantle the welfare state and they're seeking to carry out a massive transfer from the public to the private sector. That's what the big society is all about. It's on a different level to what Margaret Thatcher did and the Lib Dem leadership has thrown itself into it hook, line and sinker.

What drives you personally?

I was brought up with an inherent sense of fairness and the need to see social justice. Whether that was being brought up in a mining village or whether that's from being in the union since 1980, I don't know. Working on the front line as a benefits clerk and seeing the impact poverty has could have left me with a sense that we can do a lot better than this.

Have you traced your biological parents?

No. I consider my parents to be the people who brought me up.

You've been called "an unreconstructed Trotskyite". Are you?

I would class myself as a socialist. Not a New Labour version. A real socialist.

How did you feel when the Tablet listed you among the 100 most influential Catholics?

It caused a wry smile. No matter how many times you leave the club, the club doesn't allow you to leave. My mother, if she was looking down, would be proud, as was my sister who wrote a piece about it for the parish magazine. But I broke with the Virgin in my 20s and don't consider myself a Catholic.

Why?

As I grew older and saw the world around me, I increasingly saw problems and the answers were not provided by religion. My philosophy is to try and change the world we live in now. There's no point toiling away hoping for a better life when you die. You've got to change it now. That brought me into conflict with the teachings of the Church… it absolutely coincided with me first dipping my toe into politics.

If you had to be stuck in a lift with one of the main party leaders, who would it be?

Ed Miliband. I'd explain why he's making a massive mistake positioning himself in the centre and condemning the recent strikes was very ill-informed. If he had the guts to put himself at the head of the opposition to the austerity cuts, his popularity would rocket.

The Polish are famous for their sweet teeth. What is your favourite cake?

Chocolate roulade, served up with that old Catholic guilt. It never leaves you.

Dave Prentis, 61, general secretary, Unison

'I think I'm the luckiest person in the world to have this job.' Photograph: Antonio Olmos for the Observer

Married with two daughters, Prentis has been since 2001 general secretary of Unison, the public-service union and the country's second largest. He is responsible for 1,500 staff and a turnover estimated at £160m. He went to a Catholic grammar school in Leeds and later studied economic history at the LSE. In 2000, he was diagnosed with cancer of the oesophagus and stomach and had much of his stomach removed; he is still unable to eat large meals. He also had MRSA while in hospital.

Do you feel unions are… beloved at the moment?

I don't believe they're actively disliked. Unison has more than a million women now and people might not instantly recognise what a "public service worker" is, but they understand when you say their local teaching assistant or paramedic. We now get more sympathy for our workers than almost ever before; I think it's because we've stopped banging the table every day. The public is now realising that what is said about us by the press may not always be right.

Did you feel let down by New Labour?

Very much so. In 1997, there was a real feeling of movement and being in this together to improve society. But as time went on, they just kept espousing principles of markets and privatisation which didn't appeal to a single voter. They brought in private companies, but without looking at their effectiveness. Also, after a time, no one felt excited. It wasn't working.

And the big society?

We've always been a big society in the union movement. There are no closed shops now. People voluntarily join and pay and give their own time to help other people. Why do 1.4 million people join our organisation on a voluntary basis? And these are members of the public, despite what the media might think.

What drives you personally?

It is that sense of injustice. I came from inner-city Leeds and was fortunate enough to have a good education. I don't like talking about myself, but I suppose it's the fact that so many of my members have faith in me to stand up for them. Most people just want to have an ordinary family life, look after their dependants. But more and more, they're being hit by the excesses of the rich. I think I'm the luckiest person in the world to have this job.

The coalition – possibly a good thing?

No. Because the starting point was that Labour lost, because Labour lost its way. I don't believe that is a good thing for working people. There is a destabilisation now of many of our local services, for no need. And I speak very much as a patient of the health service and it's absolutely tremendous.

Florida or Tuscany?

This summer… a holiday camp in Croyde Bay, Devon, for two nights.

Who, or whose ideas, would you have wiped out, given omnipotence?

I wouldn't eradicate anybody. We're public-service workers, we're here to make people better! But if there's one thing I could have stopped, with hindsight, it would be the invasion of Iraq. It changed completely the nature of the Labour government and we never recovered from it.

What is your proudest achievement?

One jewel in our crown is our learning agenda. We've taken people who've left school, who can't read or write, back into learning among their peers so they don't feel inferior and taken some all the way to a PhD. It's about having faith in the best in people and a moral compass.

What calms you down?

Gardening and Coldplay.

Mary Bousted, 51, general secretary, Association of Teachers and Lecturers

'They're robbing our pension pot to pay for the economic crisis.' Photograph: Antonio Olmos for the Observer

Born in Bolton, Bousted was an English teacher in north London schools before becoming head of the School of Education at Kingston University. In 2003, she was appointed to lead the ATL, and on 30 June this year oversaw the first-ever strike in its 127-year history.

Is the public sympathetic to your aims?

We've gone through a period where the emphasis has been on individualism, on petty, mean-minded selfishness. There's now a growing realisation that to get anything done you don't have much power as an individual but you do collectively.

Is this a turning point in union history?

This was the first time in 127 years that my union had taken national strike action. The fact that we were driven to industrial action was a key marker that things are not looking good. This dash to cut the deficit is having such an effect on our working lives, on our members' pensions, and the government was acting in the vain and confident belief that we'd make a bit of fuss and then roll over, and I think this was a clear signal that wasn't going to happen. For many of my members it was a really difficult decision.

Do strikes work?

They're a weapon of last resort but let's look at what it achieved. It got journalists up to date with the pensions debate and it meant they conducted interviews which destroyed the government's lazy arguments on fairness. And it did sway the public : many of them may not have liked us going on strike but they're now much more informed and sympathetic about the issues than they were.

You accused the government of "doing a Robert Maxwell on our pensions". Do you regret saying it?

I got a lot of stick for that but I think the analogy stands. Maxwell raided his company's pension fund to keep his media empire afloat. The government is committed to raising our pension contribution by over 50 per cent at a time of a two-year pay freeze in order to pay for a deficit caused by the actions of the financial sector. It wasn't my members involved in the sub-prime mortgage market! They [the government] are robbing our pension pot in order to pay for the economic crisis.

What drives you personally?

I'm the daughter of two teachers, I'm one of eight children, four of whom trained as teachers, and I've always believed in education as a vehicle for social justice. I believe it's very important to look after the profession and that's what I do as general secretary.

Will your daughter become a teacher too?

No, she's 21, she's a fine artist and she wants nothing to do with it! She's had a bellyful of it growing up. There's no mystique to it when they see you coming home worn-out at the end of the day.

What was your worst classroom experience?

I went to get something from the store cupboard at the back of the classroom – they shut the door and wouldn't let me out for five minutes.

Is the union movement misogynistic?

It's changing. When I arrived at the ATL in 2003, I'd never had a post in the union before and two things happened. There was doubt as to whether I could do the job, and then there was an added doubt about being a woman. Would she sell out in negotiations? But the three main teaching unions are all led by women so, in education, the atmosphere has changed. I would never say misogyny isn't alive in parts of the union movement, but all sorts of things have changed. Deals used to be done in pubs and smoke-filled rooms. Now, no one drinks or smokes. Everyone is much more professional and rigorous.

Do you believe in God?

I can't believe in an omniscient being but my parents raised me as a Catholic and I do believe that every hair on my head is counted and that I'll be judged.

If you were a pop song, what would it be?

"Sisters Are Doing it for Themselves".

Brendan Barber, 60, general secretary, Trades Union Congress

'People are facing a real squeeze on living standards.' Photograph: Antonio Olmos for the Observer

Born in Southport, Lancashire, Barber joined the TUC in 1975, working in posts including media and industrial relations before becoming general secretary in 2003. He is married with two daughters and supports Everton Football Club.

Is the public sympathetic to your aims?

Yes, particularly now when we're still dealing with the consequences of the financial crisis. People are facing a real squeeze on living standards, worries about pensions and job security and in these times people turn to the unions.

What about those who say the public sector should stop moaning because they've all got gold-plated pensions?

Austerity measures are not just affecting the public sector. They have ramifications for the private sector, too, most obviously in construction, which is now in the doldrums.

What do you think of the coalition government?

I think they're cutting for ideological reasons. Clearly, they present the issues in terms of dealing with the deficit but lying behind that there is an agenda about shrinking the state and David Cameron's idea that "any willing provider" should be able to come in to deliver public sector services. That's opening the gateway to massive privatisation and a loss of accountability. We've seen some of the consequences of that with the Southern Cross episode where hundreds and hundreds of millions of pounds were taken out of that business in profit while elderly residents were left worried and anxious about where they were going to live.

What drives you personally?

A passion for social justice. We're facing a long-term crisis in this country. It's not just the last three years since Lehman Brothers collapsed. There is a pattern of change in our economy leading to an increase in inequality on a huge scale.The economy has doubled in size but the earnings of ordinary people are not remotely keeping pace. As wealth is increasingly sucked up by the elite, there are major dysfunctions we have to deal with.

You've been at the TUC since 1975. What has been the major change in the political landscape in that time?

The Conservative government led an explicit onslaught on trade unionism and we did see membership fall. There used to be over 7 million people in manufacturing. Now it's 3 million. Trade unionism took a hit as a consequence of that change and one of the consequences of the weakening of the trade unions has been increasing inequality.

On the bright side, didn't you meet your wife through the TUC?

Yes, she was a TUC official.

Was it love at first sight?

Our eyes met across a table tennis table in the basement of Congress House.

How's your golf handicap these days?

I used to play off four, now I'm up to 13 and heading north rather than south. But I enjoy it and it's an important source of relaxation.

Do you find it hard to relax?

The job is full-on. There are phone calls and meetings through the weekends and evenings.

Is it true you grew up in a borstal?

My father was a bricklaying instructor there. For my first 16 years we had a house within the grounds and I'd see the boys out and about.

Did the experience affect you?

I was certainly conscious of my dad having a strong public-service ethic and trying to give the lads a better life.

Union bosses are said to meet over "beer and sandwiches". Do you have a favourite sandwich?

Ham and cheese. Boring but classic.

Matt Wrack, 49, general secretary, Fire Brigades Union

'This is the toughest moment in our history.' Photograph: Antonio Olmos for the Observer

Born in Manchester, Wrack worked for 22 years as a firefighter before being elected to lead his union in 2005. He is divorced with two children.

What is the most pressing problem facing the union movement in Britain?

The austerity agenda. Pensions are a huge issue across the public sector, as well as job cuts and pay freezes, so it's coming from three angles.

Is the public sympathetic?

There is obviously a big offensive against the public sector and we have to battle against that. But we did some polling after the general election and found high levels of support for firefighters, and many people concerned about the impact of cuts on their local fire stations.

Are the cuts ideologically driven?

One of my concerns is the ideological consensus – that a Labour government would have done something similar. We don't care who is doing it; we'll just protect our members. This is all about making the majority pay for a crisis sparked in the banking sector.

What is your proudest achievement?

Being elected general secretary after working as a firefighter for 22 years. And if we come through the next few years intact, that will be something of an achievement. This is the toughest moment in our history.

Do you miss being a firefighter?

I did enjoy it. I miss the camaraderie. It's a great honour to be doing what I do and I try to go and meet members as often as I can. I'm conscious that, in this job, you can get out of touch.

Who is your hero?

Former general secretary John Horner, who built the union. He was a London firefighter and general secretary before the second world war. All the standards he set up in the postwar period are now being attacked.

So not anyone from Backdraft then?

[Laughs] No. We scoff at things like Backdraft and London's Burning.

What made you become a firefighter?

It was my dad who suggested it.

Was he in the same line of work?

No, he was a journalist actually.

Another honourable profession?

Ha ha! Journalists don't come out too well of what's been going on recently, do they?