There is something ineffable about Key’s comedic presence – even a legend like Steve Coogan has admitted that upon meeting his future co-star he struggled to work out “why what he was doing was funny”. While the Partridge gig did give Key a profile boost, this unpinpointable idiosyncrasy has kept him a cult figure, even within British comedy. Now, improbably, it looks as if it might make him a mainstream global star.