Smith’s Doctor – a performance which draws on elements of Albert Einstein, Charlie Chaplin and Inspector Clouseau – is very much his own creation: a high-energy, high-intelligence, yet borderline-unhinged character. “I really like the episode in the last series where the Doctor moves in with a landlord played by James Corden,” says Smith. In it the Doctor is trying to pass himself off as a regular lodger. “We see the Doctor behaving in a way which he believes to be normal but which is in fact bizarre. But we forgive him because he does it with such spirit and good grace. He’s not afraid to be himself – which is liberating and endearing. He’s never underhand – just a bit mad. I want to embrace the madness and push it further!”