Green’s Dictionary of Slang

1. (UK prison, also carpeting) a three-month sentence.

[1903		‘No. 77’ Mark of Broad Arrow n.p.: Your ‘Auto-leyne’ cares little about a ‘drag’ (three months), a sixer (a ‘carpet’ it is generally called), or a ‘stretch’].
1930		(con. 1910–20s) D. Mackenzie Hell’s Kitchen 118: Carpet ... three months’ imprisonment.
1938		F.D. Sharpe Sharpe of the Flying Squad 238: He’s a great philosopher and regards ‘a carpet’ (three months’ hard labour) as a restful period that will keep him away from the booze.
1941		V. Davis Phenomena in Crime 89: The Yard knew a ‘carpet’ (three months’ sentence) would only be a temporary suspension of Manning’s activities.
1958		F. Norman Bang To Rights 153: The chances are I would have been sentenced to carpet.
1962		B. McGhee Cut and Run (1963) 101: I wasn’t really cribbing about my sentence. I was quite happy with a ‘carpet’.
1962		R. Cook Crust on its Uppers 58: She got nicked for a carpet.
1975		‘P.B. Yuill’ Hazell and the Three-card Trick (1977) 123: If tomorrow brought a three-year lagging, or a year’s stretch or a three month carpeting — well, it was all in the game.
1979		F. Norman Too Many Crooks Spoil the Caper 201: He’d sell his only daughter down the river for the price of a packet of fags, if she wasn’t already doing a carpet in Holloway for shoplifting.
1981		(con. 1900–30) A. Harding in Samuel East End Und. 281: You’ll get a carpet for it.
1989		J. Morton Lowspeak.
2011		Spitalfields Life 18 Nov. 🌐 “Carpet” means three. That one goes back to years and years ago, when people was given a prison sentence, and if what they got was it was either three months or three years, they got a carpet in the cell and that’s what they used to say. How d’you get on? Oh, I got a carpet. Oh, fuck me, did ya?

2. £3, £30.

1954		Picture Post Jan. in DSUE (1984).
1989		in G. Tremlett Little Legs 193: carpet three months’ imprisonment; can also mean £3 or £30.