There has been a military force in Britain for much longer than the legacy of the current British Army goes, but the Royal Army is descended from Oliver Cromwell's New Model Army, which was formed by the Parliamentarians during the English Civil War to fight the armies of the Royalists. Dates vary by source, but the year 1645 is often cited.
1940 is rubbish answer. The correct answer is that the first officially organised Police Force in the World - not just the UK - was set up by Sir Robert Peel in 1829. Where you got the answer 1940 from I have no idea.
The British Army came into being with unification of the Kingdoms of England and Scotland into the United Kingdom of Great Britain in 1707.
British Army was created in 1707.
British Salonika Army was created in 1915.
British Army of the Rhine was created in 1945.
British Indian Army was created in 1857.
Future British Army Structure - Next Steps - was created in 2008.
American Army
The Continental Army
The Continental Army.
The Continental Army
The Continental Army
The Continental Army
How do Get enrolled in the British Army when I am from another country? What are the requirements of being in the British Army? Will I get a chance to be recruited in the British Army?
It was a Colonel in the British Army to keep his troops in shape