The twin pillars of Tory pro-Europeanism, the two men who defended that lonely cause in the Thatcher heyday and through the long trudge of the Major years, have responded very differently to Brexit. On one side stands Michael Heseltine, belated darling of the remainers, the lion in winter who won a deluge of Twitter love for his speech before a vast crowd at last month’s People’s Vote rally, where he spoke lyrically of his lost European dream. And there, on the other, is Kenneth Clarke, 79 this summer, not in the House of Lords but still slugging it out as a working MP, on his feet asking pointed questions, moving amendments in nail-biting midnight sessions, even tabling the alternative Brexit proposal – continued membership of a customs union – that came closest to success, falling short by just three votes.

It is not merely that Hezza, as Clarke calls him, has retired from the Commons while Clarke is still there: Father of the House, no less, in recognition of the fact that he has served continuously since 1970, a record matched only by Dennis Skinner. It also points to a deeper difference. Clarke is a devout pragmatist, an evangelical realist. Pro-European he may be, but that faith is trumped by his deference to “the real world”, a phrase he uses no fewer than five times when the two of us meet in his corner office at Portcullis House.

And so, while Heseltine or the next generation of (formerly) Conservative pro-Europeans such as Anna Soubry are holding out for a second referendum that might keep Britain in the EU, Clarke is committed to accepting reality, as he sees it. “Unless and until I can see an opportunity of actually reversing Brexit and restoring a stable membership of the European Union, then in the real world I concentrate on minimising the damage,” he says, sitting behind a desk that could only belong to Ken Clarke. (On it are several copies of the Nottingham Post; a cassette of Artie Shaw’s greatest hits; and a small booklet that turns out to be the Rules and By-laws of the Garrick Club.) “Only an ideologue deals with the world as he would wish it to be, as opposed to the world as it is.” When he recalls Edward Heath, the first Tory prime minister Clarke served as a frontbencher, he describes him as a “fanatic pro-European”. It is not a compliment.

Clarke in his office, behind a desk that could only belong to him. Photograph: David Levene/The Guardian

This is how Clarke, so vehement a pro-European he once championed Britain joining the euro, has found himself breaking from his one-time comrades in the cause, becoming instead an advocate of soft Brexit. It has made him that rare creature on the Conservative benches: a Europhile MP who has voted for Theresa May’s deal three times, filing into the aye lobby against the ultras who dismiss it as not Brexity enough and the remainers who see it as too Brexity to stomach.

It has been lonely for the former chancellor, former home secretary and serially defeated Tory leadership candidate. “That’s why I’m so annoyed by the fact that nobody’s been able to compromise: everybody votes everything else down apart from their own perfect solution. I have made a very considerable compromise.”

It has been compromise upon compromise for him. When he proposed his customs union amendment, he did it with no love or enthusiasm. It was, he admitted, no more than a “lowest common denominator”. For one thing, it called only for a customs union. “Again, pragmatic old me, not the customs union.”

He knows that’s not good enough. “I personally am desperately anxious that we stay in the single market for economic reasons. And I think we should retain the closest links we can, politically, and within the fields of security and criminal justice enforcement and so on. But it was a start. At least it didn’t exclude anything else.”

Why not hold out for the big prize, of staying in the EU? Winning a second referendum would deliver that, and then he wouldn’t have to compromise. The great European project that has dominated his working life could live on. “Great friends of mine, political friends as well as personal friends, like Michael and Anna, are convinced that another referendum can save us the whole thing,” he concedes. But he just can’t bring himself to join them. “I think referendums are ridiculous. One opinion poll with a simple yes/no answer to a question that contains hundreds of complex questions. Referendums are designed to get round parliamentary government, and people only demand referendums when they think they can’t get a majority in parliament.” He takes a breath. “Mussolini was the most brilliant practitioner of referendums.”

But no one’s urging Clarke to become a habitual user of referendums. Just one, to deal with the mess left by the last one. “Just one they think they might win,” he says of the second referendum crowd, warming to his theme, talking over several attempts I make to interject, although doing it with that trademark laugh in his voice that ensures he never seems rude – a technique that made him one of the Conservatives’ most effective messengers on the airwaves for four decades. “Unless remain won by an enormous majority, I don’t think it would solve anything. I think it would just lead to bitter, angry division, which is already there among the public. I think the campaigning would almost certainly be as silly as it was last time.”

However much Brexit appals him, referendums seem to appal him more. Throughout our conversation, he refers to the ballot of 23 June 2016 as “one opinion poll”. In which case, should parliament simply have ignored the vote to leave, carrying on as if nothing had happened? Seriously, if he were in charge, what would he have said to the British electorate the day after they had voted for Brexit?

“Somehow I would have to say: ‘Well, it’s not quite as simple as that. Leaving the EU probably isn’t going to make the faintest difference to most of the things that so annoy you. What I will take on board is that you feel so angry about the ruling class and politicians, and the establishment and so on.’ Because anger was the main emotion let loose by the referendum campaign and since.”

Which is not to say he is dismissive of those who voted leave or what motivated them. He links the leave vote to “what’s going wrong in every western democracy: Trump, the yellow jackets, anarchists in Italy”. He explains: “We achieved considerable economic success from the 1980s, 1990s, onwards, which hugely advantaged the young, the educated and the entrepreneurial. We neglected that bulk of the population being left behind and living in post-industrial towns where their living standards were static or falling. And the new globalised economy, the rules-based order, the digital revolution meant nothing to them.

Clarke (left) in 1985 with Norman Tebbit and Margaret Thatcher. Photograph: Alamy

“People want scapegoats: they blame foreigners and immigrants. You know, for Trump, it’s all the fault of the Mexicans. For the British, it’s all the fault of Brussels. Now, I blame the political class to which I belong – the establishment, of which I was undoubtedly a member – for failing to see this coming.”

So he does include himself in this failure? Yes, he says. “I did not see it coming.” He represents “the prosperous part” of Nottinghamshire, where the schools were good and house prices were high. But in the old mining towns, the signs were there. He admits he should have seen them earlier.

Still, others bear the chief blame for the current nightmare. He looks back on what will soon be a half-century in parliament and notes what he calls “the symmetry of my career: I started the year we were joining the European Union, I’m finishing when it looks as though we’re leaving”, and thinks he was lucky that his time coincided with EU membership, a period when Britain at last discovered its role in the world: “We found our vocation as a European power.” But then came that dreaded opinion poll, as he calls it, in 2016. “The whole thing’s been thrown away by a silly whim of David Cameron, who thought he’d get some short-term, party political advantage by running this stunt.”

What about May herself, whom he famously was caught calling a “bloody difficult woman”? “She is a bloody difficult woman, because she gets fixed ideas in her head, she sticks to them stubbornly. But I say that with some praise.” So we shouldn’t blame her for this mess? “Oh, it’s not Theresa’s fault. She has walked into the biggest collection of political problems facing any prime minister in my lifetime, with the possible exception of Clement Attlee. Most of them would have been overwhelmed by what she inherited. And she has qualities, among them the rather stubborn doggedness and sense of duty of a traditional home counties Tory lady.”

He refers to Attlee several times: “Quite a hero of mine.” He has praise for Tony Blair, too, as “a good prime minister who made one catastrophic mistake which I bitterly opposed, the invasion of Iraq.” How might Blair have handled Brexit? “He had the political skills; he might well have made a better job of it.” John Major, meanwhile, “would have been worried sick by it”. But at the top of the list is the woman he served for so long: “Margaret was the best prime minister of my lifetime. Mythology has turned Thatcher into someone regarded either as a goddess by her supporters or an evil witch by her opponents. She was a very pragmatic, rather odd, distinctive, determined woman with very, very forceful leadership qualities and absolute determination which might have got her through.” It’s a surprise to hear Clarke describe Thatcher as “pragmatic”. One more reason why he says: “Theresa May is no Margaret Thatcher.”

What would Thatcher have done? The very thought of it makes Clarke smile. Watching her wrestle with Brexit would, he says, have been “quite something”. He’s quite clear on one thing, though. “She was never in favour of leaving the European Union. She got exploited by hardline Eurosceptics in her dotage. When she was in office she was very pro-Europe economically, [even if] deeply suspicious of political Europe.”

Clarke (right) in 1999 with then prime minister Tony Blair (centre) and Michael Heseltine at the launch of a cross-party Britain in Europe campaign. Photograph: Stefan Rousseau/PA

How would she have voted in 2016? “She would have voted remain, just as she campaigned very heavily to remain” in the 1975 referendum. True, she had a “bad temper towards Europe towards the end” but that was “because she got on very badly with [German chancellor Helmut] Kohl and [French president François] Mitterrand, who patronised her … They weren’t quite ready for a woman being their political equal, which she certainly was.”

Yet another Tory leadership election is looming; Clarke must have lost count of the number he has witnessed. He won’t say who he likes: “That would be the kiss of death.” Intriguingly, he tells me he has spotted “some very substantial men and women” on both the Labour and Tory benches among those elected in 2010. They’re the ones to watch.

All this talk of leaders and leadership nudges us towards the fact that he never made it himself, despite attempts in 1997, 2001 and 2005. What kind of prime minister would he have been? “Sometimes kind people put me in the category of good prime ministers we might have had. It’s a very good club to be in. Denis Healey, Roy Jenkins, Rab Butler, Geoffrey Howe. And I will say it’s the best club to be in because nobody ever knows how bad you would have been if you’d ever done it.” He will say this, though. “I would have enjoyed it. That was one thing that would distinguish me from John Major: whatever else I’d have done, I’d have been determined to enjoy it.”

I hesitate before making the next suggestion, although his response tells me I needn’t have worried. Is it possible that he’s enjoying, if only a little bit, Brexit itself? After all, it revolves around the great cause of his life; it is pure, compelling drama; and he is at the centre of it. Some politicians would be offended by such a thought, or at least affect to be. Not Clarke.

“It’s hugely entertaining, if it were not so deadly serious. Oh, for a political addict, there’s nothing more fascinating than the bizarre, day-by-day, incompetent manoeuvrings that are going on. It’s like a parody version of student politics. The trouble is, the subject matter is of desperate importance to the wellbeing of next generations … I take an extremely active part in parliament not just ’cause I’m indulging myself as an old parliamentarian who’s got hooked on it. But because I’m actually having an opportunity – a privilege – of taking part in the public debate on vitally important things that matter a lot to me. I’m sure it’s doing me a power of good: it’s very therapeutic to a man approaching his 80th year and all that.”

Therapeutic seems the right word. Clarke was widowed in 2015, losing Gillian, his wife of more than 50 years, with whom he had two children. Does that help explain his decision not to retire from parliament, fighting for re-election in 2017 despite making some earlier noises about standing down?

“I normally avoid getting too personal in interviews, but my advice to all my friends who find themselves bereaved is: the best way of coping with bereavement is to keep yourself busy. Do not become a recluse, feeling sorry for yourself. Try to get busier than you usually are. That’s not the reason I’ve stayed in politics – I’m just an addict – but I think it helps. I think it helped me cope with the bereavement that I remained so absorbed and so obsessed on a daily basis with my political life, yes.”

Clarke with Theresa May at Tory party conference in 2009. Photograph: Stefan Rousseau/PA

Our time is nearly up. Clarke gamely agrees to pose for the photographer with an unlit cigar: maverick, he might be, but he’s not going to light up in his office. It strikes me that the difference between him and Heseltine might not just be Clarke’s get-on-with-it pragmatism, but that speaking of heartbreak at the loss of something he cherished for half a century – whether it’s a marriage or the European dream – is just not him.

So he will confess to feeling “dispirited and annoyed” by Brexit, infuriated by it and by a “political establishment that is spectacularly weak and unable to cope with the crisis we’ve created”, but he does not become elegiac. It is a matter of temperament. “I’m so laid-back that I’m almost horizontal, is how I would describe myself. I’m a naturally cheery and gregarious guy.”

He collects his things; he has dinner plans. I assume there’s a function to attend, maybe black tie, perhaps a speech to give. Not tonight, he says. He has a weekly semi-appointment to keep at the Kennington Tandoori: table for one, just him and a copy of the Economist. He’s looking forward to it.

• This article was amended on 13 May 2019 to clarify that Clarke’s record of having voted for May’s deal three times does not make him “rare” among Tory MPs, the majority of whom have joined him in the aye lobby on each occasion.