Military branches:
Army, Royal Navy (includes Royal Marines), Royal Air Force (2009)

Military service age and obligation:
16-33 years of age (officers 17-28) for voluntary military service (with parental consent under 18); women serve in military services, but are excluded from ground combat positions and some naval postings; as of October 2009, women comprised 12.1% of officers and 9% of enlisted personnel in the regular forces; must be citizen of the UK, Commonwealth, or Republic of Ireland; reservists serve a minimum of 3 years, to age 45 or 55; 16 years of age for voluntary military service by Nepalese citizens in the Brigade of Gurkhas; 16-34 years of age for voluntary military service by Papua New Guinean citizens (2009)

Manpower available for military service:
males age 16-49: 14,729,500
females age 16-49: 14,125,600 (2008 est.)

Manpower fit for military service:
males age 16-49: 12,123,900
females age 16-49: 11,616,769 (2009 est.)

Manpower reaching militarily significant age annually:
male: 393,892
female: 376,351 (2009 est.)

Military expenditures:
2.4% of GDP (2005 est.)