For most people, Christmas is all about spending time with loved ones.
But for personnel in the Armed Forces, the day job doesn't stop for the festive period.
This year 6,100 sailors, marines, soldiers and aviators will be deployed around the world, serving on 22 operations in 30 countries.
Military personnel will continue supporting the UK's vaccine rollout and battle against the coronavirus over Christmas, and thousands of servicemen and women will be spending Christmas deployed overseas.
But what does this part of the festive season look like for military personnel? We have taken a look at what Christmas Day involves.
For personnel who are operationally deployed, some will rotate through Christmas – taking it in turns to have a stand-down rest period and Christmas dinner while another company is on duty.
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The Royal Air Force has 24/7, 365 days a year roles to fulfill, including the work of the Quick Reaction Alert squadrons to protect the UK and RAF Fylingdales' role of tracking space objects.
The Royal Navy, which has numerous vessels around the world this Christmas, will have capabilities kept at high readiness to protect the UK at sea.
The British Army has soldiers deployed in numerous locations around the world, including peacekeeping and security taskings.
If personnel are operationally deployed, there is no alcohol allowed.
Ships usually have a two-can-a-night rule, but if a crew is in a heightened state of response, alcohol is locked away until the state of readiness drops.
If a crew is at sea, Christmas may be put on hold until their vessel is alongside again.
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For the Royal Marines training base, at Lympstone in Devon, the final week before Christmas leave is a time of celebration.
There is usually a rugby match, a carol service and a Christmas meal served by the non-commissioned officers to the junior ranks/recruits.
Despite the base being closed, as it is a training establishment, marines chefs have previously laid on a meal for elderly people around the area.
When deployed domestically, troops sometimes start their day with Gunfire, a combination of tea and rum.
There are a number of traditions, including an annual fancy dress inspection/competition among the Queen's Life Guard and judged by the Commanding Officer.
Christmas carols are sung in the station gym, with multiple festive functions taking place throughout the whole of December.