Green’s Dictionary of Slang

a prison van.

1909

J. Ware Passing Eng. of the Victorian Era 256/1: V. R. (Peoples’). Evasive reference to the prison van, which, in the reign of Victoria, bore these initials on each side. [Ibid.] 256/2: Vagabonds removed (Peoples’). Droll application of the initials V.R. – the letters standing, of course, for Victoria Regina, which appeared on the outside of the prison van to the end of the reign of Victoria.