Broadly speaking the UK's armed forces have 2 roles. The most fundamental role is that of defending the homeland the other is the defence of vital interest where ever that vital interest is.
There is no threat to the UK homeland that the military is required to address beyond terrorism. The last perceived threat was the Warsaw pact, with the collapse of that threat then Russia was held up as a threat, however unlikely.
Since the 2008 South Ossetia war Russia has taken a root and branch look at it's armed forces and has changed the centuries old Russian practice. In the past the Russian philosophy was to maintain an officer corps and equipment inventory far larger than was required for the current number of enlisted men. This allowed the fielding of a massive army on very short notice. During the 2008 war the Georgians where equipped to NATO standards and proved far harder for the Russians to deal with than they had supposed. As a result the Russians undertook a complete reassessment of their military strategy and concluded that a smaller professional army was the way to go.
This allows the Russians traditional enemies to remove Russia from the list of potential adversaries as they can no longer go from a small army to a massive army in 12 months. This removes the last overland threat to the UK, this should cause a fundamental reassessment of the British Forces Germany, Germany is in a position to protect itself and does not need the 1.5 billion Euro subsidy from the UK. With more than 25,000 troops in Germany that is 2.5 times more than are in Afghanistan and as far as I can tell Germany has been peaceful for some time. They of course have equipment as well which must consist of around 200 Challenger 2 and more Warrior IFV.