Rory Stewart has just arrived at KFC in Barking. It’s day four of “campaigning proper”, as he puts it, for the Tory leadership. The International Development Secretary has chosen Barking because it is a no-deal Brexit enclave and he wants “to talk to Leave voters.”

Margaret Thatcher did this, he says, hammering on doors with Labour stickers in the window to convince them their economic analysis was wrong.

Stewart believes this shows “sincerity”. “What I will find in Barking is people who’ll disagree with me strongly. If my campaign is about being unifying and inclusive I have to have the confidence to go out and … talk to them. ” His argument is for a managed deal. He describes himself as “radical centre”.

Later he posts a film of himself doing a selfie piece-to-mobile-phone-camera while walking down the street, and another speaking Dari to a constituent (Stewart lived on-and-off in Afghanistan for three years from 2005). The response is he’s indeed “barking” but charming. Earlier in the day he met Remainers in Borough. Among them, a woman who’d seen his documentary on Afghanistan and a man who’d heard one of his podcasts. Another guy “clearly had no idea who I was.” Another told him “You’re the only Tory I’d vote for.” Unfortunately, sighs Stewart, “he was a Lib Dem.”

Stewart is certainly the outsider — he’s polling last in the race — but it’s instructive that he has hired Lizzie Loudon, a press secretary with experience of Number 10 under Theresa May, and is happy to admit he has the “vanity and ego” befitting a contender. He believes his time as a diplomat and adventurer (whose account of a month-long walk through Afghanistan The Places In Between became a bestseller) was the perfect apprenticeship for the job.

He’s an unusual character, 5ft 9in, wire-thin in his tailored suit and knitted green tie. Even with a new hair cut, his style is artfully dishevelled. He wears thistle cufflinks, a nod to his Scottish roots, and a gold signet ring, and he looks like a cross between Mick Jagger, Eddie Redmayne and the puppet from Interpol’s Evil video.

What kind of Tory is Stewart? On the one hand he is the Eton-Balliol kind, like Boris Johnson. On the other, he’d never voted Tory before 2001 — and only then, to his chagrin, because his father and mother – a former deputy head of MI6 and a “true blue Tory, Brexiteer and cornerstone of the Perth and Kinross Conservative Association” — cast his proxy vote while he was away in India. Between the ages of 18 and 21, he was a fully-paid up member of the Labour Party while helping Princes William and Harry with their Maths and English. Royal tutor and Labour member? “Yes,” he laughs. “That’s the kind of Tory I am.”

In today’s political landscape, your position on the EU is as important as party colours. Stewart wants both no-deal and a second referendum “off the table”. His proposed method of finding “compromise in the middle ground” is, “painful though this sounds, locking the MPs up and bashing a deal through.” He would do this with “a Macron-style Citizen’s Assembly” with the Archbishop of Canterbury in the role of “mediator”.

He means to include “literally everyone” in talks, citing ERG hardliner Mark Francois, Unite boss Len McCluskey and, “if necessary”, Nigel Farage. The important thing is to “lift our heads up from the day-to-day Brexit squabble to what the long-term objective is here,” he says. He’s already collared McCluskey in the street after they appeared on a BBC politics show together.

Today, he appears to make the decision to talk to Farage mid-sentence after relating that they had dinner six weeks ago at the Oxford Union. “I am going to get my office to reach out straight to him,” he says. “I am the last person he will expect to hear from and that is a powerful position to come from.”

Stewart may have the same pedigree as Johnson in terms of schooling but in this contest he’s the anti-Boris candidate. When we first meet (over tea in Portcullis House last Thursday) he says he would consider serving in a Johnson Cabinet for the good of the country. At some point over the weekend he rules this out. Asked if Johnson is across the detail of his brief, Stewart (who worked with Johnson at the Foreign Office) doesn’t say yes, he says he won’t be drawn into “insulting my opponents.”

But he swings from high-chivalry to waspish, saying, when asked if as leader he would rein in Johnson’s inflammatory commentary, such as comparing women in “burqas” to letterboxes, “I don’t think there’s any leader who would be foolish enough to think they could control a poet of the legendary quality of Boris Johnson. Many have tried. I don’t think he’s a racist. I think he’s an incredibly talented, very engaging journalist.” If this is supposed to be damning, it’s a shame he is talking to journalists. He describes the “point of Boris” as not dissimilar to that of Jeremy Clarkson.

Later, when drawing on his heroes, he says the thing that is greatest about Winston Churchill was his “eye for detail”: “Because real leadership is not broad-brush poetical nonsense,” he says.

In policy terms, Stewart is much closer to Michael Gove. Both are radical, both embrace tech, both are extreme green — Stewart’s stated first policy would be to plant 120 million native trees in four months. He wants to issue “green bonds” and have the Government buy land and build houses, “not nudging property developers.” He cites Edinburgh’s new town and says he wants people “in 200 years’” time to look back at the work of his government and say “‘My goodness, what an incredible civilisation.’”

But he is not convincing when asked, as a slightly Victorian character, how he will appeal to young people. “Because I care,” he says. “Because I’m sincere.”

And although claiming that it is “completely vital” to attract more BAME members and voters he is flummoxed by the question of Islamophobia in the Tories. “I may be missing it,” he admits.

His is an unusual turn of phrase —  “I am going to green DFID,” he says at one point. Things are often “a miracle.” The British car industry is “a miracle”, as are our security services, London too.

He’s at once terribly posh (“issues” is pronounced iz-use) with the odd Americanism like “gotta” (Stewart’s wife Shoshana Clark is from New York) with a manner that at times appears superior. When telling the story of how he met his wife in Afghanistan, he relates it through her eyes. “I was standing on the top of the turret of the mud castle about 25ft in the air in a suit trying to discourse with an Afghan engineer. She saw this strange person and a white dog.”

His speaking rhythm sometimes beats to iambic pentameter, perhaps because he likes to commit verse to heart. He learnt Eliot’s The Wasteland aged 14, and the Four Quartets while walking from India to Nepal in 2001, which he later recited through a megaphone in Penrith on the day he was elected in 2010.

Always simmering under the surface is the desire to talk about his experiences in Afghanistan and Iraq. “The thing I’ve learnt negotiating, whether with warring factions in Iraq or with mini-wars in Afghanistan,” he tells us, “is that you have to be nimble. This is not a game of red lines or rigidity, you gotta keep trying and be imaginative, and you have to reach out.” He says there are “similarities” with post-war Iraq and post-Brexit voting Britain. “The most fundamental similarity is that there is a completely surreal gap between the way that the Government talks about this and what is actually going on on the ground.”

Actually, his discomfort with arms sales to Saudi Arabia (“if we talk about democracy and human rights, we need to follow through on that”) mean that he has revolutionary ideas on foreign policy too. “If I were lucky enough to be Prime Minister, I would actually rebalance our foreign policy away from the Middle East towards Asia and Africa.”

He is keen to be honest. Then again, he’s occasionally nettled. On the subject of Eton, he says: “When you are choosing a leader, you’re also choosing someone who spent 550 nights sleeping on the floor of village houses across Afghanistan, Nepal and India — seeing things that many other people who went to Eton haven’t seen in their lives”.

What about rumours that he was — like his father — in the secret intelligence service? He emits a “ha”, then allows a pause. “Well, so… I mean… no.”

He didn’t know what his father did as a child but he adored him. The last time he cried “properly” was when his father died in his arms in 2015. “I was trying to resuscitate him. It was a strange moment for me because in very quick succession within nine months I’d had to deliver my first son with 999 on my telephone in my ear and I was trying to do artificial resuscitation with 999 in my ear.” He now has two boys, four and two. Yes, he changes nappies.

Asked if he has a “fields of wheat” moment of naughtiness, he says: “All these things are relative.” To illustrate he tells how he once sat with a KGB officer over a drink. He puts on a Russian accent. “‘Rory’ he said at about 3am, ‘I have broken every one of the Ten Commandments’ and he started crying. And I said, ‘My God, every one?’ And he said, ‘Yes, every one. Even I have not respected my father and mother.’ So that’s the naughtiness that I am used to.”

Is he tough enough to be PM? A toothy grin spreads across his face. “The reason I have been proud to be in Iraq, in Afghanistan, serving my country is because I believe in a Britain that is understated in its answers to those kind of questions. I don’t believe tough guys are people who say they are tough.”

Later he tells an anecdote from Afghanistan. He was in a blizzard following 9/11, “completely lost.” “Suddenly I saw bumping towards me two big Toyota Land Cruisers. The electric window came down, and there was an SAS guy who served with me in the Balkans. He stuck his head out and said: ‘You are a f**king nutter.’ And then wound up the window and drove off.”