One of the key defence partners in the 30-nation strong NATO alliance, the UK has been chosen to host a range of activities on behalf of the organisation.
British military personnel regularly take part in alliance exercises, as well as being part of air policing in Europe - this year, RAF Typhoons from 6 Squadron were based in Lithuania with the task of defending NATO airspace as part of Operation Azotize.
NATO data estimates meanwhile that there has been a defence spending increase by the UK on last year from 2.14% to 2.43% of GDP.
From intelligence gathering to warfare experimentation, below are the sites used by NATO in the UK.
Royal Naval Air Station Yeovilton
The military airfield in Somerset is one of the UK's busiest, with more than 100 aircraft from a range of units and well over 4,000 employees.
It is also home to NATO Joint Electronic Warfare Core Staff (JEWCS), providing the group with electronic warfare capability and specialised training under the same remit.
JEWCS also offers expertise on how to react to a hostile electromagnetic environment alongside other continency planning, and feeds any new information from experiments through to other NATO members.
This north-west London base was home to the RAF Coastal Command during the First World War and has gone on to become the principal UK headquarters site, hosting five operational headquarters.
One of those is Allied Maritime Command (MARCOM), one of NATO’s three major Commanders alongside LANDCOM and AIRCOM.
MARCOM is the primary maritime advisor to the alliance with about 300 military and civilian employees, responsible for planning and commanding a range of exercises and operations.
Based in Gloucester, the site represents HQ for both NATO's Allied Rapid Reaction Corps (ARRC) and Head Quarter 1st Signal Brigade.
The ARRC force dates back to the early 1990s, the Allies’ first military response to the post-Soviet world and ensuing uncertainty.
The corps was quickly put through its paces with peace interventions in Bosnia and Kosovo and moved from Rheindahlen in Germany to Imjin Barracks a decade ago.
1st Signal Brigade is made up of specialist sub-units to support NATO joint forces such as ARRC with communications technology across the globe.
The base in Dorset is home to Deployed Communication Module Delta (DCMD), part of 1 NATO Signals Battalion.
It contributes to the NATO Response Force and joins many multinational units to make up the battalion.
The role of a Deployable Communication Module is to install and control strategic communication and information systems supporting a deployed NATO headquarters.
The unit is held at readiness and has recently been recognised for its high operational tempo on recent deployments to Romania, Lithuania, and Afghanistan.
Royal Air Force Molesworth
Located close to Cambridge and closely aligned with nearby RAF Alconbury, this air station plays a vital role in defence intelligence.
The NATO Intelligence Fusion Centre (IFC) falls under the command of Supreme Allied Commander Europe and provides the alliance with intelligence to warn of potential crisis situations and support NATO Special Operations forces.
Fully operational since 2007, the organisation has produced strategic assessments for Afghanistan, Kosovo, Gulf of Aden, and Libya operations, while also referenced by military planners on behalf of the European Union.