John Simm: "We were shooting one scene, just me and David, on top of this deserted mountain-top. We’re giving it our all when, from f**k knows where, you can hear the faint sound of an ice-cream van. David carried on so I thought, well, I’m not going to stop if you’re not going to stop. So we carried on right to the end, despite the fact that this must be the only ice-cream van in existence that does the theme tune to The Benny Hill Show - the least intergalactic sound imaginable!"