5 Pounds White, signature in watermark

Bank of England five-pound whites of this period were hand-signed by a cashier and numbered individually — each note was, technically, a unique document. The "signature in watermark" variety places the cashier's name within the paper itself during manufacture at Portals Mill in Hampshire, a security measure intended to defeat the increasingly sophisticated forgeries that had plagued the Bank since the early nineteenth century. A successful forgery of a white fiver could ruin the counterfeiter's victims entirely; prosecution was capital until 1832, and the Bank's own aggressive pursuit of forgers had become a public scandal by the 1820s.

By the 1860s this format was already being phased toward greater mechanization. The watermark signature variety sits at the tail end of a craft-intensive production method the Bank would not fully abandon until decades later.