Angela Rayner is perhaps the only Labour MP who works with a picture of Theresa May hanging above her desk. It’s there for inspiration, she says, a daily reminder of the general incompetence of the Conservative government and the need for its removal. ‘That picture motivates me, in a strange way,’ she says when we meet. ‘They are doing such a bad job of Brexit, and a lot of people will be let down. Again. The people who already think that politicians are lower than a snake’s belly.’ The anger is with politicians in general. ‘It just feels that this generation is not doing a very good job.’

Ms Rayner, 37, has been a politician for not even three years and her rise has been nothing short of extraordinary. A few years ago, she was a care-home worker with an interest in politics but no career plans. She stood for Ashton-under-Lyne in the 2015 general election and ended up becoming Jeremy Corbyn’s third shadow education secretary in the space of a week. Not, she says, because she’s a Corbyn-ite, but she couldn’t work out why every-one else was resigning from his team. ‘You never, ever give up the chance to change things, ever, no matter how hard it is. If you’re elected, and have got the opportunity to make a difference, you take it.’

Her difference has been dragging Labour education policy more towards the centre, softening its hostility to free schools and prioritising nursery-care spending before subsidising university tuition fees. She has been one of Corbyn’s most effective shadow cabinet members while keeping her distance from him — refusing to sign a loyalty pledge demanded by Momentum, his personal campaign group. She’s making her own progress on her own terms: Tories talk about her as the party’s most effective shadow education secretary for a generation.

Which is quite something, given that her own schooling ended when she was aged 16 — an experience, she says, that shaped her whole political outlook. ‘I was pregnant when I left school, so I needed income support. I didn’t even have functional skills, not even GSCEs in English and Maths, so I needed to go back to college.’ She was in the same position as her mother a generation earlier but the difference for her, she says, was that by 1997 the welfare state was big enough to step in.

‘I would have been seen as a scrounger, a scally unlikely to make anything of my life. But without those interventions I wouldn’t have been able to have my son, who is having a great life and has done really well for himself. And I wouldn’t now be a taxpayer who pays their way in life, no longer on any benefits. I wouldn’t be supporting my other two wonderful children. Sometimes you have to invest in people to get the best out of them. To me, that is socialism. That is why I’m a Labour member rather than a Conservative.’

Parenthood, she says, didn’t just transform her life but might have saved it. ‘I was in the Manchester nightclub scene at 13 and thought affection from men — the wrong type of affection — was the right thing,’ she says. ‘I was going out with people a lot older than me, so was already on that slippery slope.’ Her friends, she says, slipped. ‘I lost about six friends before I was 18. They died through a drug overdose, or killed in a car, joy-riding. But once I got pregnant it wasn’t just my life I was messing around with. I had somebody to look after.’

This meant work. Her gran stepped in, offering to mind her son while he slept so she could earn. ‘That’s how I became a home help: nobody wanted to do the evening shift. I worked for an agency that would have taken anyone off the streets.’ She trained as a Samaritan, joined the council as a carer and then became involved in the trade union. This is what exposed her to politics, and its dysfunctions.

Listening to Ms Rayner explain all this, you wonder why she did not decide to join a Conservative party that had by then, under David Cameron, dedicated itself to defending the victims of bad government. ‘One of the Conservatives said to me: “You should be one of us, Ange, this is why we’re Conservatives! You’ve done well, you’ve climbed out!” But they don’t get it. My mates, who are struggling now, are no different to me. My brother and sister are smarter than me. But I’m the most successful because I’ve been given opportunities that they never had.’

Her politics are shaped not only by the opportunities extended to her, but those denied to her friends and family, especially her mother, who dropped out of school aged 12. ‘She followed the fairground wherever it went. She was almost feral, and her mum and dad didn’t care. Two of her siblings were given to a Christian couple down the road and just never came back home.’ Had government intervened, she says, things might have been different.

‘My mum’s had learning deprivation and mental health problems; she is economically not viable. That’s the penalty on society for not investing in my mum and putting those interventions in place.’

Would her mother have been considered ‘at risk’? ‘Her conversation with me was, “I couldn’t love you as a child because I could only love one person at a time and that was your dad.” That says so much about why I ended up where I was. And about why I’m not that person any more. My mum didn’t say that to be horrible, but because she wasn’t able to get emotional support.’

For Rayner, this is the point about welfare: failure to support people leads to greater economic and social cost later. She’s almost evangelical while talking about it, presenting her life story as proof. The system worked with her, she says, but it failed her mother — and both of their lives were defined by it.

When a Labour MP describes themselves as an unlikely politician driven by practicality rather than ideology, it’s normally code for having a Blairite faith in the market. Not Ms Rayner. She doesn’t want to abolish free schools, but sees them as a device that helps pushy parents and does nothing for other families. She proposes a ‘National Education Service’, an NHS for education. In reality, it’s just another badge for the idea of ‘lifelong learning’ but it would be seen to tackle deeper problems — such as, she says, the striking underperformance of the white working class.

Focusing on ethnic minorities and women’s agendas, she says, has had a ‘negative impact’ for white working-class boys. ‘They have not been able to adapt. Culturally, we are not telling them that they need to learn and they need to aspire. They are under the impression that they don’t need to push themselves, in the way that disadvantaged groups had to before. I think that is why there is a bit of a lag there. I think we need to do much more about the culture of white working class in this country.’ Her son, she says, didn’t go to university. ‘I’m quite chilled about it. But ask most parents round here how they’d feel if their kids didn’t go to university: oh!’

More school choice, she says, is not the answer, because so many parents are too busy to compare them. ‘My job is making sure that every child gets a good school place. If there is a particular disadvantage to a community, you invest more. Because that’s the Labour way.’

She has promised an extra £500 million for Sure Start nurseries and wants even bigger economic changes, including nationalisations. ‘We are in different times, radical times where we need to have a real investment in Britain’s future. Genuinely. I don’t mean that as a slogan, I mean it as an economic strategy.’ Quite a gamble, she admits. ‘It is a bit of a shit-or-bust strategy, I get that. It’s a high-risk strategy. But all of Britain’s great advancements in the past have been because we’ve had the gumption to take a risk.’

She talks as if she is still an outsider, at odds with the system and its trappings. When she was named rising star of the year at the Spectator Parliamentarian awards, she joked that she was not used to lavish dinners and hadn’t seen so many knives on a table since the last Stockport police amnesty. So is she settling in now, or does she think, like her fellow Labour MP Laura Pidcock, that the House of Commons ‘reeks of the establishment’?

Yes, she says, of course it does. ‘But I’ve had that all my life. I’ve always had that: where people have looked down on me. I still get that, to this day. In this place, some people do that. And I think: well, you look down at me at your peril, mate. Because I’ll just eat you alive.’