Military branches:
Army, Royal Navy (includes Royal Marines), Royal Air Force (2013)

Military service age and obligation:
16-33 years of age (officers 17-28) for voluntary military service (with parental consent under 18); no conscription; women serve in military services including some ground combat roles; the UK’s Defense Ministry is expected to further ease existing women's restrictions by the end of 2016; must be citizen of the UK, Commonwealth, or Republic of Ireland; reservists serve a minimum of 3 years, to age 45 or 55; 17 years 6 months 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 (2016)

Military expenditures:
2.07% of GDP (2015) 2.2% of GDP (2014) 2.3% of GDP (2013) 2.49% of GDP (2012) 2.48% of GDP (2011)
country comparison to the world: 28
[see also: Military expenditures country ranks ]