Michael Palin has chosen a Spanish-influenced restaurant for our rendezvous. I tell him I’m grateful as it means I can make a pun about no one expecting it, in much the same way as no one ever expected the Spanish Inquisition in the Monty Python sketch he co-wrote.

“Well it’s not a pun, it’s a play on words,” he says with professorial firmness as he takes a seat at his favourite window table in Moro on London’s Exmouth Market. He gives a benign smile and the crinkles spread across the planes of his face like contour lines. He’s right, of course. It isn’t technically a pun.

At 71, and despite a varied career involving travel documentaries, TV and film acting and scriptwriting, Palin remains inextricably linked with the enduring appeal of the recently reunited Monty Python.

Palin was in his 20s when he started writing comic sketches with his Oxford contemporary, Terry Jones. Later, the duo joined forces with John Cleese, Graham Chapman, Eric Idle and Terry Gilliam. The first series of their surrealist comedy series aired in 1969.

Some of the Pythons’ most famous setpieces were dreamed up by Palin. The Spanish Inquisition sketch, for instance, in which unsuspecting members of the public are assailed by a group of red-robed, mustachioed priests, was written by him in “less than an hour, probably.”

“It was real stream-of-consciousness,” he says, ordering a starter of sardines accompanied by a glass of sherry. “It just happened. And when we filmed it, I was wearing this hat which was too big so I had to keep pushing it off my eyes and I went off thinking, ‘This is going to be disastrous.’ But it’s the one people remember.”

He takes a thoughtful sip of his sherry. The drink reminds him of his parents. It was the only alcohol they consumed and they stored it in a cut-glass decanter at home in Broomhill, Sheffield. His father, Edward, was an engineer for a steel firm and had a debilitating stammer.

“He was quite, sort of, enclosed,” says Palin, “and quite difficult sometimes. He had a quick temper. I think all of those things came from the frustration at not being able to speak fluently.”

I wonder whether watching his father struggle himself somehow influenced Palin’s decision to become a performer; whether his own need for self-expression was more acute because of it?

“I think, growing up, I sensed that. And it may not be what encouraged me to travel or do lots of the things I’ve done but it certainly encouraged me to try to be agreeable and sociable and friendly.”

Palin was sent to boarding school in Shrewsbury. It was “quite tough – we had fagging and all that – [but] sometimes, when the world is not exactly to your liking, humour is a good way of dealing with the problem.”

In the school holidays, away from the fagging and the lumpy semolina, Palin remembers eating his mother’s liver and onions and her delicious treacle tart, made with “a lot of oats”. Is he a good cook?

“No.” There is an awkward pause. “Shall we abort the interview now?” he asks, laughing.

He has simple tastes, favouring fresh fish and anything chargrilled – “Burnt stuff. Burnt toast. Anything with carbon on it.” Palin’s idea of food heaven is a “filled baguette with pastrami, cheese and a little bit of mustard, a bit of tomato in there as well. I love bread with food.”

As if to prove the point, he takes a chunk from the bread basket and dunks it lustily in a saucer of olive oil.

The third volume of his diaries is about to be published and friends of his who read the earlier instalments have joked that he always seems to be out for lunch. The new book does indeed record a number of fine meals, including one at the Ivy where Cleese happened to be dining at the same time. He sent over a half-empty bottle of water “with the compliments of the table”. Palin responded by sending back a salt dish.

“I get tetchy without food,” Palin admits (this, too, is mentioned more than once in the diaries and attributed to his “Taurean” personality). “And because of the work I do, a lot of it is done in convivial circumstances,” he adds.

Actually, there isn’t that much dining out in the diaries. The 550-page volume is mostly filled with amusing and revealing anecdotes (like the time he discovered Cleese was writing jokes for the Dalai Lama). The book also charts Palin’s reincarnation as a television adventurer and opens with him embarking on the filming of Around the World in 80 Days. He reveals himself to be full of self-doubt during the shoot, anxious that he isn’t doing a good enough job and restless to get on with the next project. How did he find having to recall all his worries?

“It’s a bit like group therapy with yourself,” he says as his second course of chargrilled mackerel arrives at the table. “You relive moments and it can be quite difficult. But it’s also oddly reassuring. You think you’ve changed and, actually, you’re completely, exactly the same as before.”

As it turned out, 80 Days was a commercial and critical hit, leading to several other documentaries and tie-in books. These days, taxi drivers are more likely to recognise him from the travel programmes than Python. They ask him for holiday tips: “Or they’ll say: ‘My wife loves you.’”

He was appointed a CBE in 2000 and has been referred to, more than once, as “Britain’s Nicest Man” – although the accolade rankles.

“It’s become a sort of cliche that’s attached to me,” he says, angrily skewering a flake of fish. “I just think I’m reasonably courteous, I avoid confrontation, I’m interested in people... I’m not particularly argumentative, but that could apply to lots of people. OK, I’m quite a nice bloke, but also I can be very sulky, angry and impulsive.”

The five surviving Pythons recently completed a run of sell-out shows at the O2 in London. Palin, who had been characteristically anxious in the run-up to the event (“I thought: ‘It’s a huge arena, a lot of publicity, we’re really setting ourselves up if it doesn’t work’”) ended up having a whale of a time. His wife, Helen, a bereavement counsellor, came five times because she loved the atmosphere so much. His daughter Rachel (he also has two sons and two grandsons, aged eight and five) saw three shows, even though none of his children had been particular fans of Monty Python when growing up.

“Suddenly her estimation of me went up by leaps and bounds,” Palin says and his eyes film over. He must have enjoyed it – he’s about to embark on a one-man tour.

What was it like, being reunited with his old compadres? Has the group dynamic stayed the same over the years?

“It’s probably the same but exaggerated slightly,” he says, washing down the last of his fish with a glass of white rioja. “Eric’s become a very successful showman, John’s getting married to people, Terry Jones is worrying about things, which he always did, and Terry Gilliam has just become more and more manically inventive but also, sort of, completely doomy and gloomy about everything – in a spectacularly positive way. He’s made moaning into a real art form.”

As for Palin? I should think he is just the same too – restless, anxious, kind...but mildly irritated everyone around him thinks he’s so bloody nice.

Travelling to Work: Diaries 1988-98 (Weidenfeld & Nicolson, £25) is out now. Click here to order it from the Guardian Bookshop for £20 with free p&p.

Michael Palin’s one-man show tours the UK until 22 October