Video: Jon Knighton reports from the race.
66 cars, including civilian teams, were hoping to get off to a quick start as they lined up at Silverstone, the British home of motorsport.
The format of the six hour race has remained virtually unchanged since the first one took place in 1951, with a handicap system awarding credit laps to less powerful cars.
Before the race even started, the Army faced difficulty with three of their cars in need of repairs.
Following tradition, the handicap committee hit the defending champions hard.
The RAF's most powerful car was limited to a maximum of 25 laps, and their least powerful car to a minimum of 20 laps, to qualify for their 29 credit laps over the six hours.
Last year's champions, the RAF, were pursued earlier on by the Army, a mixed forces team and for the first time, a Royal Navy and a Royal Marines team.
Although the race began dry, a forecast of rain prompted the RAF to switch their running order, putting Armed forces Champion Ed McKean out first.
During the dry spell, the Navy excelled with Keith Atwood, supported by Richard Scott, James Cantwell, Mike Wells and Simon Vernon.
The Army were also in the mix - Chris Wood in his Ashley GT Midget survived a cylinder head gasket change, whilst Matt Taylor, Mark White, Sy Skerton and Will Ashmore were all driving well.
However, they were left at a major disadvantaged as Farard Daver's BMW remained in the pits, despite the best efforts of the Army mechanics team.
But as rain started to fall on the track, the RAF's master wet driver, Darren Berrys, came into his own.
Despite only being allowed to do 25 laps in his powerful Westfield V8, the RAF driver did enough to push the RAF up the rankings.
The RAF's Darren Howe, Dan Smith, Simon Frowen and Scott Lawson also played their part as the RAF went onto lift the Inter-Services Birkett title again.
In the handicap race, the RAF finished 9th, the Armed Forces Challengers 10th, Team Brit (made up of injured personnel) 22nd and the Royal Navy 33rd.
As the Army were unable to get Darver's BMW on the track, they had to settle for 58th.