Abingdon Street is in Westminster and runs along Old Palace Yard (SW1). Some say the name was derived from Mary Abingdon, the lady who is supposed to have written the letter which led to the discovery of the Gunpowder Plot. "At the commencement of the eighteenth century, Abingdon Street is described as 'a narrow lane, pestered with coaches, which render it dirty and inconvenient'" (Reference: Walcott's Memorials of Westminster, p. 318) .