Green’s Dictionary of Slang

1. a programme, a plan.

1928

T.W.H. Crosland ‘Signs of the Times’ in Last Poems 57: ‘We’ gave the Admirals ‘a prog,’ / ‘We’ set the dates and kept the log.

2. a radio or TV programme, e.g. the J.Y. prog, the Jimmy Young programme.

1951		K. Amis letter 2 Dec. in Leader (2000) 264: All I ask is, when you introduce a selection of your stuff on the 3rd prog., remember the old pall.
1972		New Scientist 15 June 644: A new series of BBC-2 commences at 8 pm: [...] In tonight’s prog, Anthony Smith has a look at the world’s newest national park.
2000		Indep. Rev. 15 Jan. 8: Jimmy Young [...] was swift to take up the baton on his ever-topical ‘prog’.