As Roald Dahl’s regular illustrator, Quentin Blake drew snozzcumbers and Willy Wonka’s chocolate factory. But even such a colourful imagination as his can struggle to comprehend the mysteries of NHS bureaucracy.

Mr Blake sketched a new logo for Whittington Health Trust in north London: a goggle-eyed but chipper looking black cat, which was rejected by the trust as it did not “adhere to strict guidelines to ensure consistency of the NHS brand”.

In emails obtained by local paper the Camden New Journal going back to March 2011, the trust said it had planned to use the new cat after gaining foundation trust status. Its bid has been dropped twice after it failed to meet Monitor’s conditions, meaning it has to stick to strict rules about its logo.

Perhaps, after the branding cat-astrophe (pun intended) of “2gether Foundation Trust”, Monitor was worried the Whittington might seek inspiration from singer-songwriter Prince by adopting the doodle as its name. No wonder it took a dim view!

At the launch of one of his exhibitions this year, Mr Blake said of the Whittington debacle: “I never quite understood what happened.” He wouldn’t be alone in being baffled at the some of the more obscure appendices of the NHS rulebook.