If you remember, when I took over, no one thought it would work. I was ‘too young’. David (Tennant) had come from a stellar era. I was unknown. For a month or two when I started I was like, ‘This is impossible. I can’t’ — just the pressure of it. Everyone was sort of going, ‘Go on, show us what you’ve got.’ I told myself, ‘If I can get through this I can get through anything’. Matt Smith on what it was like to first take on the role of The Doctor