The UK is set to announce plans to obtain nine Boeing P-8 Poseidon maritime patrol aircraft, as well as extend the service life of the Royal Air Force’s Eurofighter Typhoon fighters.

The P-8 acquisition and Typhoon life extenstion will be part of a £178 billion ($270 billion) investment that will be made in defence equipment and support over the next ten years, says a statement from the prime minister’s office.

Prime Minister David Cameron will outline the plans when he unveils the Strategic Defence and Security Review (SDSR) in the House of Commons later today.

With the last of the RAF’s British Aerospace Nimrod MR2s having already been retired in March of 2010, the cancellation of the replacement Nimrod MRA4 indefinitely extended a so-called “capability gap” to what had long been considered an indispensable national skillset.

“These roles require an aircraft that can carry torpedoes, as well as being fitted with a broad range of sensors, including radar and sonobuoys, which are operated from the rear of the cabin by a team of specialists,” says the statement. “These aircraft will also provide maritime search and rescue and surveillance capabilities over land.”

The statement adds that the service life of the Typhoons will be extended 10 years to 2040. This will allow two additional squadrons, bringing total frontline squadron strength to seven, with 12 aircraft per squadron.

“We will also invest in their ground attack capability and fit them with a new Active Electronically Scanned Array radar to ensure they can continue to operate in hostile environments in the future,” says the statement.