The Ministry of Defence has announced a host of new deployments in recent weeks in response to building tensions with Russia, culminating with the invasion of Ukraine last week.
Additional British troops, tanks and other military equipment have been sent to Estonia, near Russia's border, while Royal Navy ships are at sea and RAF jets are carrying out missions over Poland and Romania, intended to reassure allies.
Here's a breakdown of where UK military personnel are currently deployed across the continent.
Type 45 guided-missile destroyer HMS Diamond has deployed to the Mediterranean after a short delay due to a technical defect.
She is due to join up with HMS Trent, currently deployed with other NATO vessels in the eastern Mediterranean.
HMS Trent is an Offshore Patrol Vessel and is lightly armed but does carry a detachment of Royal Marines.
Watch: HMS Diamond set sail for the Mediterranean on Friday.
Also in the region is HMS Echo, a multi-role survey vessel. While she specialises in survey work, she is armed with some light weapons.
The Royal Navy has vessels deployed in Norway too. HMS Albion, for example, an amphibious assault ship, is currently in Tromso, ahead of a NATO exercise, after setting sail from Devonport last week.
HMS Portland, Northumberland, and Defender are all also at sea, all in the vicinity of the UK.
The Royal Navy's two aircraft carriers, HMS Queen Elizabeth and HMS Prince of Wales are alongside in Portsmouth. The latter is due to deploy later this month to join NATO exercises off the coast of Norway.
The British Army has maintained a presence in Estonia since 2017, as part of NATO's enhanced Forward Presence (eFP) programme.
The alliance says these deployments, which also include a Canadian-led force in Latvia, a German-led force in Lithuania, and an American-led force in Poland, "make clear that an attack on one ally would be considered an attack on the whole alliance".
Watch: Extra British troops and equipment arrived in Estonia last week.
The UK has now deployed an additional 1,000 troops to Estonia, as well as further Challenger 2 tanks.
In early February, an extra 350 troops were also sent to Poland, adding to the 100 troops already in the country.
Defence Secretary Ben Wallace said last week that the UK's deployments "constitute a credible deterrent to stop Russian aggression threatening the territorial sovereignty of member states".
Royal Air Force
Alongside Voyager air-to-air refuelling tankers, jets based both in Cyprus and the UK are conducting flights over Romania and Poland as part of NATO's air policing mission – designed to protect the alliance's airspace.
Also in the area is an RAF submarine hunter P-8A Poseidon maritime patrol aircraft – the jet is currently deployed to Sicily, taking part in NATO exercises.
Watch: More RAF Typhoons arrived in Cyprus in February.
Intelligence-gathering aircraft have been seen active near Ukraine. A Royal Air Force RC-135W Rivet Joint surveillance aircraft has flown several times since Russian forces invaded Ukraine.
On 23 February, a day before Russia's invasion began, the aircraft was seen on flight tracking website flightradar24.com flying a pattern over Ukraine. Since then, it has been conducting flights over Poland, near the country's border with Ukraine.
According to the Royal Air Force, its "sensors 'soak up' electronic emissions from communications, radar and other systems".