One colloquial (slang) term is "Squaddies" Previously they were known as Tommies after Thomas Atkins, the name on the specimen sign-up papers.
Tommy Atkins, or more often just 'Tommy'
another name for the british are lobsterbacks and redcoats
Recoats. Tommies
Tommy Lobsters!
Lobsterbacks
Name given to the British soldiers by the people of Boston was the "redcoats".
In the revolutionary war, soldiers of the British Army were called Red-Coats.
Redcoats was another name for British soldiers because of their red uniforms.
Tommy
If you mean British soldiers, you could replace British with United Kingdom or UK and soldiers with troops, infantry, military or army personnel.They were nicknamed Tommies in the past century. During the American Revolution they were "redcoats" due to their uniforms.
Lobsterbacks.
tommies
Redcoats