Green’s Dictionary of Slang

akip adj.

asleep.

1958		F. Norman in Sun. Graphic 23 Nov. in Norman’s London (1969) 40: There was one young geezer fast akip on the stairs.
1962		F. Norman in Police and the Public in Norman’s London (1969) 128: The next thing I knew I was fast akip.
1974		G.F. Newman You Flash Bastard 219: He figure Juliet would at least have been in bed, if not asleep. [...] ‘I figured you’d have been akip.’.