Gosh, I used to sing this, but can't recall all the words at the moment. I'll start you off anyway.

Standing alone in the dust and the dark,
of a dirty old phone box in Finsbury Park.
I asked for Freemantle, they gave me a FRO
I asked for a Primrose, they gave me a PRO.

Cho
Say who you are love and not hello
Give me your name or give me your number
Say who you are love and not hello
If I press button A, all my pennies will go.

PRO was Prospect, and FRO was Frobisher, which along with Primrose and Freemantle, were the names of London telephone exchanges. When dialling you used the first three letters, followed by the number.
In those days there was a black metal box in the booth, with 3 slots on the top for coins. A standard phone call cost 4d, four old pennies. In the front there were two buttons marked A & B, and if somebody answered, you pressed button A, and you 4d dropped into the box, and you made your call. If no reply you pressed button B and your money was returned via a small chromed cup on the front of the box.
It was a common practice of mine, and others, to pop into a phone box when passing by, in the hope that somebody had forgotten to do so, and there was still pennies to be had.