London: British Prime Minister David Cameron is to promise an additional £12 billion ($18.2 billion, 17.1 billion euros) to strengthen the defence forces when he unveils a five-year strategic review on Monday, according to a government statement.
The Strategic Defence and Security Review will set out Britain's priorities for the duration of his Conservative government, and will focus on tackling threats such as Islamic State group as well as hostile states.
Under the plans there would be nine new maritime surveillance aircraft, and two "Strike Brigades" able to quickly deploy missions up to 5,000 strong, according to a government statement.
"At its heart is an understanding that we cannot choose between conventional defences against state-based threats and the need to counter threats that do not recognise national borders," Cameron wrote of the strategy in a foreword to the review.
"Today we face both and we must respond to both.
"So over the course of this parliament our priorities are to deter state-based threats, tackle terrorism, remain a world leader in cyber security and ensure we have the capability to respond rapidly to crises as they emerge."
Britain has committed to meet a NATO target of spending at least 2 percent of gross domestic product on defence.
It will include extending the lifespan of the Royal Air Force's Typhoon jets by 10 years. Additional funding for special forces has already been announced, as well as a 30 percent rise in counter-terror spending.
Cameron will launch the Strategic Defence and Security Review in the lower house of parliament on Monday.
Cameron is due to make the case for Britain joining international air strikes against IS in Syria, after the United Nations Security council authorised countries to "take all necessary measures" against IS following the attacks in Paris that killed 130 people.
