The UK is a leading country in the world, with a seat at the Security Council of the United Nations. As such it has responsibilities to contribute to UN peace keeping and peace making missions, and to humanitarian interventions around the world. The UK is also a leading member of NATO, a crucial defensive alliance for the western democracies. The UK is the second largest spender on defence after the USA in the alliance, and agrees with President Trump that the non US partners need to make a larger contribution to their own defence than they have been doing. The UK has agreed to spend 2% of its GDP on defence, which means that each year as GDP rises defence receives a cash and a real increase in its spending levels.
The UK needs several important capabilities. It needs an expeditionary force, so that it can intervene decisively, usually with allies, where there are events like the invasion of the Falklands or Kuwait that require a swift and effective military response. It needs a similar ability to project force over distance to assist with peace making interventions in regional wars as sometimes in the Middle East, and to have humanitarian capability to assist victims of flood or disease or other disasters. Above all the UK needs a strong defence to protect these islands, which includes the insurance of a nuclear missile shield to deter aggression.
The government has found the money for two large carrier ships and attendant planes. It is proceeding with the renewal of the submarines which contain the nuclear deterrent, which need to have a continuous at sea capability to be effective. It has reduced the size of the surface navy, the army and the airforce as it has sought to adjust to tighter budgets in the last twenty years.
Extra money would be welcome to expand the surface fleet needed to complete and protect the carrier groups, and to provide flexible task forces for humanitarian purpose and to provide home defence. It could be used to relieve the pressures for a smaller army, which stretches UK ability to respond positively to the demands of allies and the UN to contribute to missions. It could add to the number of aircraft, as we resume a maritime reconnaissance ability and strengthen the heavy lift capability. To be a successful expeditionary power we need eyes in the sky and the ability to move people and equipment rapidly to trouble spots.