Downing Street said the nine new Boeing P8 maritime patrol aircraft would offer maritime surveillance, anti-submarine and anti-surface ship warfare capability, increasing further the protection of Britain’s nuclear submarines and new aircraft carriers. They will also provide maritime search and rescue and surveillance capabilities over land.
These roles require an aircraft that can carry torpedoes, as well as being fitted with a broad range of sensors, including radar and sonobuoys.
Plans for a new generation of Nimrod aircraft, formerly based at RAF Kinloss, were scrapped in 2010.
The Prime Minister will give details of an additional £12 billion of equipment funding when he sets out the Government’s National Security Strategy and Strategic Defence and Security Review (SDSR) in the Commons.
He will also announce a 10-year extension to the operational lifespan of the RAF’s Typhoon jets and upgrade work to give them ground attack capabilities - effectively adding two additional frontline squadrons.
But unions are braced for the SDSR to include plans to slash thousands of civilian Ministry of Defence (MoD) posts to cut costs.
Defence spending received a boost in the Budget, when George Osborne, under intense pressure from MPs and defence chiefs, declared that the UK would continue to meet a Nato target to devote at least 2% of national wealth to defence.
Mr Cameron said the UK was the only major country to meet both its Nato commitment and an obligation to spend 0.7% of national income on aid - and was doing both due to “clear-eyed self interest”.
Speaking at RAF Northolt ahead of his Commons statement, the Prime Minister said: “This is showing that there is no economic security without national security and vice versa.
“We have now got a stronger economy and we can choose, rightly, to invest more in our national security - more ships, more planes, a bigger navy, a bigger RAF, a better equipped army, better in terms of fighting cyber attacks and fighting terrorism.
“Britain is the only major country anywhere in the world that both meets its Nato spending targets and meets its aid commitments.
“We are an engaged nation, not for reasons of national vanity but for reasons of clear-eyed self interest. What goes on in the world matters to the United Kingdom and so we should be helping to shape it.
“And with today’s announcement we can do just that.”