Back of Rackhams

Rackhams was a large Department store located in the English city of Birmingham. The Alley way at the rear of Rackhams was a notorious 'Red Light' area and synonymous with prostitution.

The store was taken over by 'House of Fraiser' in 2003, but the saying persists with the old name

She's been working round the Back of Rackhams ( suggesting loose morals of a female)