A US Navy Boeing Poseidon P8 aircraft sits on display at the Singapore Airshow in this file photograph dated February 11, 2014.[Photo/Agencies]

LONDON - Britain will invest an extra 12 billion pounds ($18 billion) in defence equipment over the next 10 years including nine Boeing submarine-hunting aircraft, Prime Minister David Cameron said on Monday.

Cameron will set out a five-year defence and security plan to parliament on Monday focused on making sure Britain is able to respond to a variety of threats including the rise of Islamic State militants, the crisis in Ukraine, and cyber attacks.

"This government has taken a clear decision to invest in our security and safeguard our prosperity," Cameron wrote in the foreword to the review, published in advance by his office.

"We cannot choose between conventional defences against state-based threats and the need to counter threats that do not recognise national borders. Today we face both and we must respond to both."

He will announce defence equipment spending will rise to 178 billion pounds over the next decade, including investing in nine Boeing P-8 Poseidon maritime patrol aircraft which will help protect Britain's nuclear deterrent and fill a gap left by a decision to scrap the Nimrod spy-plane programme in 2010.

Britain will also create two rapidly deployable, 5,000-strong "strike brigades" by 2025 and extend the life of its Typhoon fighter jets by 10 years to create an extra two squadrons.

Writing in the Telegraph newspaper on Monday, the British leader also said the government would invest in new surveillance drones and make a joint investment with France in developing unmanned combat air vehicles.