20 Pounds Bank of Ireland

Bank of Ireland's £20 series of the early 1980s was printed by De La Rue in London at a time when the Irish pound still tracked closely against sterling — the two currencies had been at parity until the Republic joined the European Monetary System in 1979, after which the punt began to float independently. That decoupling made denominations like this one politically as well as economically significant.

Watermark-only security was already considered minimal by the early 1980s; De La Rue had more sophisticated options available, and the relative simplicity of the protection on this series reflects cost and procurement decisions at the Bank of Ireland rather than any technical limitation of the printer.