The tri-service badge of the British Armed Forces
The armed forces of the United Kingdom, commonly known as the British Armed Forces, Her Majesty's Armed Forces or the Armed Forces of the Crown, encompasses the British Army, Royal Air Force and the Naval Service (Royal Navy and Royal Marines).
The British Armed Forces are charged with protecting the United Kingdom and its overseas territories, promoting Britain's wider security interests, and supporting international peacekeeping efforts. They are active and regular participants in NATO and other coalition operations, including recent operations in Afghanistan and Iraq and ongoing peacekeeping responsibilities in the Balkans and Cyprus
The British Armed Forces have a reported combined personnel strength of 429,500 in 2006 (195,900 regular force, 191,300 regular reserve, and 42,300 volunteer reserve). It constitutes one of the largest militaries in Europe by troop count, though only the 28th largest in the world. The British Armed Forces however have the second highest expenditure of any military in the world, only behind the USA.
The Commander-in-Chief is the British monarch, Queen Elizabeth II and they are managed by the Defence Council of the Ministry of Defence. Consistent with longstanding constitutional convention, however, the Prime Minister holds de facto authority over the armed forces.