20 Pounds

These notes bear Special Identification Markings ("war codes"), consisting of a coloured letter inside a circle as part of the underprint in the upper left and bottom right of the obverse. These were used during World War II to keep track of notes during transport from the printers in the United Kingdom in case of losses due to bombing.
Only one letter appears on £20 notes, A in blue.

For similar notes see P#5, P#5D, P#60 and P#67.
Currency Commission Irish Free State: P#5
Central Bank of Ireland with promise to pay in London and war code letters: P#5D
Central Bank of Ireland with promise to pay in London, without war code letters: P#60
Central Bank of Ireland without promise to pay in London: P#67

A complete list of dates of issue for Irish Legal Tender One Pound Notes is on www.irishpapermoney.com, along with an image of a note of each date, as well as an introduction to the design of the 20 Pound note featured here. These Legal Tender Notes, ‘Lady Lavery’ Series A, circulated in the Irish Free State and Republic of Ireland from 1928 to 1977. Denominations of 10 shillings, £1, £5, £10, £20, £50, and £100 were issued.