Green’s Dictionary of Slang

carpet n.2

[rhy. sl.; carpet-bag = drag n.1 (5); or f. the earlier assumption that prison workshops took just 90 days to produce a particular type of regulation size carpet. But note def. in cit. 1903. However, note Michael Quinion (WWW 6/5/00): ‘I suspect No 77 made a mistake, since “carpet” came about as the result of a bit of rhyming slang: “carpet-bag” = “drag”, implying that the two words have always meant the same thing’]

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

[‘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’].
[US](con. 1910–20s) D. Mackenzie Hell’s Kitchen 118: Carpet ... three months’ imprisonment.
[UK]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.
[UK]V. Davis Phenomena in Crime 89: The Yard knew a ‘carpet’ (three months’ sentence) would only be a temporary suspension of Manning’s activities.
[UK]F. Norman Bang To Rights 153: The chances are I would have been sentenced to carpet.
[UK]B. McGhee Cut and Run (1963) 101: I wasn’t really cribbing about my sentence. I was quite happy with a ‘carpet’.
[UK]R. Cook Crust on its Uppers 58: She got nicked for a carpet.
[UK]‘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.
[UK]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.
[UK](con. 1900–30) A. Harding in Samuel East End Und. 281: You’ll get a carpet for it.
[UK]J. Morton Lowspeak.
[UK]Spitalfields Life 18 Nov. [Internet] “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.

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

In phrases

double-carpet (n.)

(UK prison) six months’ imprisonment.

[UK]D. Powis Signs of Crime 181: Double carpet Six months imprisonment: ‘Did he get bird?’; reply, ‘Yes, a double carpet’.