Of the money spent on UK defence, about £3.3 billion can be attributed to Scotland as of 2018/2019.
Scotland had a long military tradition predating the Treaty of Union with England; the Scots Army and Royal Scots Navy were (with the exception of the Atholl Highlanders, Europe’s only legal private army) merged with their English counterparts to form the Royal Navy and the British Army, which together form part of the British Armed Forces. Numerous Scottish regiments have at various times existed in the British Army. Distinctively Scottish regiments in the British Army include the Scots Guards, the Royal Scots Dragoon Guards and the 154 (Scottish) Regiment RLC, an Army Reserve regiment of the Royal Logistic Corps. In 2006, as a result of the Delivering Security in a Changing World white paper, the Scottish infantry regiments in the Scottish Division were amalgamated to form the Royal Regiment of Scotland. As a result of the Cameron–Clegg coalition‘s Strategic Defence and Security Review 2010, the Scottish regiments of the line in the British Army infantry, having previously formed the Scottish Division, were reorganised into the Scottish, Welsh and Irish Division in 2017. Before the formation of the Scottish Division, the Scottish infantry was organised into a Lowland Brigade and Highland Brigade.
Because of their topography and perceived remoteness, parts of Scotland have housed many sensitive defence establishments. Between 1960 and 1991, the Holy Loch was a base for the US fleet of Polaris ballistic missile submarines. Today, Her Majesty’s Naval Base Clyde, 25 miles (40 kilometres) north-west of Glasgow, is the base for the four Trident-armed Vanguard-class ballistic missile submarines that comprise the Britain’s nuclear deterrent.
Scotland’s Scapa Flow was the main base for the Royal Navy in the 20th century. As the Cold War intensified in 1961, the United States deployed Polaris ballistic missiles, and submarines, in the Firth of Clyde‘s Holy Loch. Public protests from CND campaigners proved futile. The Royal Navy successfully convinced the government to allow the base because it wanted its own Polaris submarines, and it obtained them in 1963. The RN’s nuclear submarine base opened with four Resolution-class Polaris submarines at the expanded Faslane Naval Base on the Gare Loch. The first patrol of a Trident-armed submarine occurred in 1994, although the US base was closed at the end of the Cold War.
A single front-line Royal Air Force base is located in Scotland. RAF Lossiemouth, located in Moray, is the most northerly air defence fighter base in the United Kingdom and is home to three fast-jet squadrons equipped with the Eurofighter Typhoon.