As part of a set of defense decisions that British Prime Minister David Cameron described as delighting President Barack Obama, the British government announced plans to purchase nine P-8 Poseidon long-range patrol planes from Boeing through a foreign military sale approved by the US government. The Poseidon, the aircraft built by Boeing to replace the US Navy's aging Lockheed P-3 Orion antisubmarine warfare patrol aircraft, will fill the gap left by the retirement of the Royal Air Force's Hawker Sidley Nimrod fleet over four years ago, and the cancellation of the UK's own follow-on aircraft. It means about $1.5 billion more in business for Boeing and its partners; the Poseidon currently has a "flyaway" cost of $171.5 million per aircraft.

The P-8 is based on the Boeing's 737-800 with modified wings and a strengthened fuselage. The plane's main sensor is its AM/APY-10 multifunction radar, a high-resolution radar that can be used both over sea and land for surveillance of surface targets, and as a weather radar. It has a bomb bay that can be used for dropping torpedoes as glide bombs from an altitude of up to 30,000 feet, and it can carry SLAM-ER standoff land-attack missiles, Harpoon anti-ship missiles, and an assortment of other missiles, mines, torpedoes and bombs in addition to its sonobouy air-dropped acoustic sensors. A modified version is already flown by the Indian Navy.

The Poseidon purchase is part of a larger effort to increase the size and capability of the RAF and the rest of the UK's military—a £12 billion ($18.1 billion) increase in the nation's defense budget and part of a £178 billion ($270 billion) program over the next 10 years put forward in the government's five-year National Security Strategy and Strategic Defence and Security Review, which Cameron presented to the House of Commons today. The programs planned will also extend the life of the RAF's Eurofigher Typhoon fighters, adding two additional Typhoon squadrons (for a total of seven) and keeping the planes in service until 2040. The UK will also buy an additional squadron of F-35 fighters for the Royal Navy beyond the UK's original commitment.

The Poseidon aircraft will be based out of Scotland and will be used for maritime patrol "to protect our nuclear deterrent, hunt down hostile submarines, and enhance our maritime search and rescue," according to the security review document. The Poseidons could also be used over land for electronic surveillance and intelligence collection, target tracking, and search-and-rescue missions.

The increased budget proposed by Cameron is part of a NATO commitment to raise defense spending to two percent of gross domestic product. The UK has the second largest defense budget in NATO, trailing only the US.