My Old Man Said, Follow The Van according to Wikipedia is a music hall song written in 1919 by Fred W. Leigh and Charles Collins, made popular by Marie Lloyd.
The song, although humorous, also reflects some of the hardships of working class life in London at the beginning of the 20th century. It joined a music hall tradition of dealing with life in a determinedly upbeat fashion. In the song a couple are obliged to move house, after dark, because they cannot pay their rent. At the time the song was written, most London houses were rented, so moving in a hurry – a moonlight flit – was common when the husband lost his job or there was insufficient money to pay the rent.
The couple rush to fill up the van, and its tailboard, with their possessions, in case the landlord appears. When the van is packed up, however, there is no room left for the wife. The husband therefore instructs her to follow the van, which she does, carrying the pet bird. Unfortunately, en route, the wife loses her way after stopping at a pub for a drink. Thereafter, she reflects that it would be ill-advised to approach one of the volunteer policemen (a \"special\"), as they are less trustworthy than a regular police constable (a \"copper\") and might take advantage of her inebriation. Alternatively (according to the physical gestures accompanying the song) they may simply be less qualified to give dependable street directions.
Normally sung by a lady, you will just 'ave to use yer imagination' as I sing it.
\"An old 'alf quarten\" was a slang expression for a measure of spirits (usually gin) and was equal to 2½ Imperial ounces.
