I wondered how long it would be before Andy Warhol’s "15 minute" quote came up. From the whizzy, flash-bang opening credits I knew it wouldn’t be long. I was right: but less than seven minutes? Less than five? I didn’t time it, since I was still somewhat mesmerised by the sight of perky presenter Alastair Sooke doing a kind of disco-dancey, pointy-arm manoeuvre in front of Picasso’s Les Demoiselles d’Avignon during the intro. (Oh no, Alastair, I wanted to cry, you can’t out-cool Andy, so don’t even try.)