Ask Ben Whishaw about acting and he twists in his chair, pushes his hair into various shapes, and, avoiding all eye contact, mutters: "I find it really hard to say anything coherent or interesting about the work I do." But ask him, out of slight desperation, about the government's cuts to the arts and he sits up sharply and squares his shoulders. "We're really going to feel it. I'm frustrated by the whole situation because I'm not sure I believe what we're being told about the deficit problem. It's frightening to see public services being cut and libraries being closed. Closing the UK Film Council felt shockingly barbaric."
Whishaw has rather taken me by surprise – not because he has opinions about government policy, but because he gets so flushed and angry on the subject. On screen, he tends to use those huge, vulnerable eyes to portray defenceless characters – most memorably as the young man accused of a murder he didn't commit in the BBC's five-night series Criminal Justice back in 2008. It turns out that he is even better at feisty characters. In The Hour, the BBC's forthcoming six-part spy thriller set in London in 1956, he is captivating as a passionate, cocky journalist who will stop at nothing to get his story. The first episode opens with a closeup on Whishaw's face, his hair gelled into position, announcing: "Newsreels are dead. We've bored the public too long." Society gossip and the benign news story are over; it's time for a more investigative, political approach.
Whishaw's character, Freddie, wants a job as presenter of The Hour, a groundbreaking topical news programme – but it goes to the well-connected, privately educated Hector Madden (a super-smooth Dominic West). Both men are enthralled by their tough, ambitious producer (a terrific performance from Romola Garai). Abi Morgan's tight script gives a strong sense of an edgy, postwar Britain suddenly confronted with the Suez crisis; and of the immense political pressure on The Hour (and the BBC) not to question Britain's military response.
The early and inevitable comparisons with Mad Men are perhaps misguided. The American series is, after all, set in the 1960s and is more stylised, self-conscious even. Whishaw won't be drawn into a beauty contest, and claims to have seen only an hour of Mad Men on a plane. He talks instead about researching the social history of 1950s Britain, the fact that Morgan gave each of her central characters three pages detailing their back stories, and about playing a journalist. "It made me value what they do," he says. "It's fun to pretend you're good at something you know you wouldn't be good at in real life. I loved researching the era, but Abi created a complete world which I just had to step into."
He falters when asked about the process of getting into character. This is possibly his least favourite question. He is vague about the experience of playing one of six Bob Dylans in the Todd Haynes film I'm Not There, but says it's great when he's turned on by the material: he loved getting into Dylan's poetic side (he plays the singer as Arthur Rimbaud) and became completely immersed in Keats before playing the poet in Jane Campion's Bright Star. But how does he unlock a character? He must think about it just a little bit? He looks scared. "I really don't!" Is it about being good at empathy? "I'm just curious about how other people look at things. I'm definitely interested in how everyone carries around a universe. But once I've finished a role I tend to let it go completely – I can't remember much about it."
He's not even sure why he got into acting in the first place. He grew up in Hitchin, Hertfordshire, as a fraternal twin ("My brother is much fairer and bigger than me. He's got a good jaw and is handsome"). His father was in IT, his mother worked in a department store. He recalls auditioning for the local Bancroft Players' Youth Theatre at 14. "I did Hamlet for some reason. And one of the first productions was a mix of two Primo Levi books. Oh yeah, I was hardcore early on."
As a child, he loved Marlon Brando and Jimmy Stewart, and was good at art. He had an Athena poster of the lost city of Atlantis on his wall and kept a collection of trinkets. "I used to collect knick-knacks like wizards, trolls and little buddhas and arrange them like precious things on a shelf. Why am I telling you this? It was an odd thing to do. I don't know what became of them." He looks at the floor, embarrassed.
A lot of actors hide behind their characters, and a lot of actors claim to be shy, but Whishaw does this more than most. It's hard to imagine the awkward, self-deprecating boy-man in front of me striding into an audition or commanding a film set, yet he clearly does. When he was 23 and just six months out of Rada, he was asked by Trevor Nunn to play Hamlet as a five-year-old for his audition at the Old Vic theatre in London. "I didn't take it literally. It was one of those weird, intuitive things that was meant to unlock something. I think he was getting at the idea that five-year-olds have feelings very near the surface. I ended up playing Hamlet as a teenager who is very alienated from the world."
As mesmerising as he can be on screen – and he looks particularly good in The Hour's tweed suits – there is something about Whishaw that is temperamentally unsuited to acting. He never reads reviews because a bad one would paralyse him. He says his family are always concerned about him – "by nature they have a tendency to worry neurotically".
I ask if he isn't a worrier, too, and he smiles. "Probably. I'm definitely very moody." There is another awkward silence, so I ask what he sees when he looks in the mirror? He looks crushed. "Probably all the things I don't have. All the things I lack. I feel acutely aware of that at the moment, I don't know why."
And yet he should be in a good place: he has just spent two weeks travelling in Cambodia, Vietnam and Laos, and is planning a trip to India ("I'd never been out of the west before, and now I'm hooked. I love having no idea what day it is"). He is filming the part of Richard II in an epic BBC film and doesn't seem to be short of work. Are the looming cuts likely to change this – is he personally feeling the effects? "I've certainly felt the industry change since the financial crisis. It's just harder to get things made." Still, he is permanently drawn to acting and loves the company of other actors, once they've got over "sniffing each other like animals". But the self-doubt is hard to overcome. "It's the constant feeling of not quite achieving what you'd hoped. It often creeps into my mind that I might give up acting."
He laughs, aware of how lucky he is and how ungrateful he might sound. "I'm hopeless at interviews. I'm sorry. If we were at a dinner party, I'd be very different. I wouldn't want to talk about my work. But I'd certainly tell you what I think about those bloody banks."
• The Hour starts on BBC2 in July.
