Green’s Dictionary of Slang

Polari n.

In compounds

Polari pipe

a telephone.

P. Baker Fabtabulosa 47: polari pipe [...] noun: a telephone.
[UK]P. Baker Fabulosa 296/2: polari pipe a telephone.
[UK]R. Milward Man-Eating Typewriter n.p.: I picked up the polari-pipe immediately, clogging the switchboard with demands for a bona crocus.