Who was the Prime Minister of the United Kingdom in 1919?

David Lloyd George, who was the first Welshman to hold the office.

He replaced Herbert Asquith as Prime Minister in 1916 in the middle of WW1, following disagreements within the War Cabinet over policy in handling the conflict. He was present at the Treaty of Versailles in 1919, was the PM who finally gave women the vote (although only if they were over 30), and was in office up until October 1922.

He died in 1945 aged 82, soon after the end of WW2 in Europe.