"You're not playing that berk are you?" The Crown's Matt Smith and Claire Foy explain how they've fallen for the royal family

Watching Smith look effortlessly majestic in Prince Philip’s scarlet Grenadier Guards uniform during filming at Clarence House, you’re also reminded that he was incredibly dashing.

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“The facts of the situation are that she was completely infatuated with him. He was a dreamboat,” says Claire Foy, who has wowed audiences with her portrayal of the Queen.

“But they also had a lot in common and they seemed to understand each other in a way that was really special. They had a common sense of humour, and a common way of communicating.”

The Crown’s smash-hit first season for Netflix sprang a few surprises on the Windsors’ loyal subjects, not least of which was how much of a wildcard match Philip was for Elizabeth and how far he would have been from the first choice of a royal-marriage-arranger. It was a love-match island in a sea of duty.

By the start of season two, however, their marriage is miserable. The year is 1956 and the Duke of Edinburgh is restless in his helpmeet role and missing his naval career.

More importantly, he has fallen in with a bad crowd, and has a “thing” going on with a ballet dancer. Alienated from the Queen, he goes off on a tour of the Commonwealth and, free from the scrutiny of the press, controversially grows a beard.

“There’s an interesting balance to be struck,” Smith explains, “between trying to be truthful and authoritative and not being too syrupy. You only need to go a little bit in this direction and it’s too reverent; and in that direction, and it’s too liberal and sneery and anti-them.”

The whole project, written by Peter Morgan (the man who also brought us Helen Mirren in the 2006 film The Queen), is a tightrope between staying true to the facts and telling a story that gets to the root of a relationship about which so little is known.

As Claire Foy says, “What everybody doesn’t know about the royal family is that there are no facts. It’s all conjecture. That’s what Peter does so well. He doesn’t place the truth anywhere. He leaves it for people to figure out for themselves.”

Matt Smith adds, “This is the reason that they’ve endured – they’ve never allowed us behind the palace walls. They’ve kept the illusion, that mystique.”

Into that lacuna of discretion where decades of gossip should be, The Crown has poured a universal story of marital disappointment and disillusionment, laced with the very specific circumstance of this family, at that time: they could never divorce; they could only endure.

“There is a fracture in their marriage that neither of them is quite willing or able to address. Their problems are universal. The things that touch them are the things that would touch anybody,” Foy says. “But that feeling that there is no way out… it’s easier to understand when you realise their marriage is the symbol of Christianity in the United Kingdom.”

For all the sparse and elegant tenderness of the script, the great wells of sorrow in Foy’s eyes when she’s playing the Queen and the stubborn, battened-down anguish in Smith’s Duke speak volumes on their own. It helps that they’ve both fallen, totally, for their characters.

“He was essentially orphaned,” Smith explains. “His mother was committed, his father went off to Monaco and he was sent off to live with his uncle.”

Add in an education at Gordonstoun boarding school in the Highlands, which became known as Colditz in kilts, and Prince Philip becomes a much more human character.

The Queen, though, probably comes off as the most beset this season, battling the Suez Crisis brought on by a flapping Conservative government led by Anthony Eden (brilliantly played by a thin-lipped Jeremy Northam).

“Looking back at the decisions people made [during Suez], you can see them in a context and maybe that reminds us all to just pause for a moment before making choices. Because you’ve got to accept the consequences,” says Foy.

It seems that, like the royal character she plays on screen, Foy has developed a delicate diplomacy, never sounding thoughtless or Pollyanna-ish, always treading carefully.

But you can’t help thinking that despite talking about Suez she is drawing a parallel with Brexit. “The Crown shows that a lot of people who were in charge didn’t take those consequences into consideration. They were only concerned with their moment in history, as opposed to thinking of generations to come, who would live with what they decided to do.”

Asked whether the series has made her more of a monarchist, Foy says, “As far as I’m concerned, I live in a country that has a monarchy and I appreciate everything they do. I have huge respect for Elizabeth and her family and the things they’ve done as people. The monarchy as an institution is a very complex thing, and it’s not necessarily something I identify with.”

Claire Foy was born to play British royals – her performance as Anne Boleyn in the BBC adaptation of Hilary Mantel’s Wolf Hall was magnetic. “Well, I’ve always been fascinated by Anne Boleyn, but we all have, haven’t we? Come on. She had six fingers! She’s always been an exotic bird.”

This is The Crown’s final season for the current protagonists in their young incarnations: season three will be recast, though we’ve no more details as yet, other than that Olivia Colman will play the Queen in her middle years.

It’s clear how much the current leads have been drawn into the Windsors. “Prince Philip’s my barometer on everything,” Smith says stoutly, “even on whether or not to have an Instagram account [neither of them does]. I have been inhabiting him for the last two years.”

And yet both Smith and Foy have made their peace with the recast. Foy is a free spirit and couldn’t imagine being pinned down by anything. “This idea that, when you get to be a grown up, you’ve got to have sorted everything out and live the same life… I think the expectation that anyone is ever going to do that is slightly ridiculous.”

Plus, she says, the pressure of the second series is already a burden: “It’s more difficult because you can’t try to re-create what made it successful the first time around. You have to just approach it as if you’ve never done it before, and you have to be attentive, and not let things slide, and not be complacent.”

Smith, meanwhile, has experience of walking out of a part at the peak of his performance – his Doctor Who regenerated into Peter Capaldi. “Oh yeah, I’ve been through it, I always knew it was going to happen. It’s absolutely not a problem; it’s one of the things that gives the show a real chance of having a life cycle.”

Doctor Who, in one way, was a different beast altogether. “From the moment I was cast, I’d walk down the street, and people would come up to me and go, ‘You can’t break the Doctor.’”

Yet, while the difference in popularity of these two parts is stark, they’re ultimately not so different, Smith points out. “They’re more similar than you’d think: they’re both sort of aliens, both outcasts. Now that would be a great episode – Doctor Who with a young Prince Philip.”

The Crown season two is available to watch from Friday 8th December on Netflix