George Lyon Duncan Rewcastle was born in 1890 to deaf parents, machine fitter George Rewcastle and Clara Emily Rewcastle.

It is not known when he attended Westoe Secondary School. However, after school he was employed by the South Shields Corporation in the Weights and Measures Department and, in 1913, was appointed Weights and Measures Inspector in Stoke-on-Trent.

He enlisted with the Royal Garrison Artillery in November, 1914, and was promoted to 2nd Lieutenant in October, 1915 and went to serve in France.

At Trones Wood, on the Somme, an ammunition store caught fire and, despite being knocked down twice, George Rewcastle and a gunner, were able to prevent the fire reaching boxes of small arms ammunition. For displaying "conspicuous gallantry and devotion to duty", George was awarded the Distinguished Service Order in November, 1916.

In 1917 he was promoted to full Lieutenant, and then acting Captain, and in 1918 he was promoted to Temporary Major.

After the war, George Rewcastle was transferred to the Colonial Office, and on 9-Jul-1920 was made a substantive Major.

About this time, he was appointed one of the Assistant Commissioners of Police in Nigeria. On 27-Jan-1924 he was leading a police escort in Onitsha Province. There had been a revolt in the area, stirred up by a priestess in the Juju cult.

George's detail was ambushed on its way to make an arrest, and Major Rewcastle was shot in the head at close range.