Green’s Dictionary of Slang

(UK black) amusing, funny.

2005		Observer Rev. 14 Aug. 7/2: Jokes adj. meaning funny: ‘The film’s jokes, you’ve gotta see it.’.
2010		BBC News ‘Report on Teenage Slang’ 11 Mar. [radio] It was bare jokes [...] It was very funny.
2017		theculturetrip.com ‘Guide to London Slang 10 Jan. 🌐 Jokes – funny as in ‘that party was jokes’ or ‘Charlie is proper jokes’.