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LONDON, July 18 (Reuters) - Lawmakers will vote on Monday onwhether to renew Britain's nuclear deterrent, a key decision forWestern security policy, which partly hinges on Britain as oneof western Europe's only two nuclear powers.
Parliament, where the Conservatives have a majority of 16,is likely to approve renewing the Scottish-based nuclear-armedTrident submarines over the opposition of the Scottish NationalParty and many lawmakers from the Labour Party.
Political divisions about whether to replace the Tridentsubmarines, agreed in principle by parliament in 2007, haveraised questions about Britain's standing as a world power,amplified by a vote to leave the European Union.
The newly appointed prime minister, Theresa May, is expectedto tell lawmakers on Monday that the nuclear threat is growingand urge them to put ideology aside and back renewal.
"It is impossible to say for certain that no extreme threatswill emerge in the next 30 or 40 years to threaten our securityand way of life," May will say, according to pre-released quotesissued by her office.
"We cannot abandon our ultimate safeguard out of misplacedidealism."
Labour leader Jeremy Corbyn, who has been challenged by twocandidates seeking to take the helm of the centre-left party, isopposed to nuclear weapons as a long-standing anti-warcampaigner.
Some military officials also oppose the outlay on Trident,saying the money would be better spent on maintaining the armyand on more conventional technology, both of which have recentlysuffered cutbacks.
Defence firms BAE Systems, Rolls-Royce and Babcock would all be likely to benefit from arenewal, with the new submarines expected to enter service in2028 at the earliest.
A lawmaker's and Reuters' calculations, based on officialfigures, indicate that the overall cost of replacing andmaintaining Britain's nuclear deterrent will reach 167 billionpounds ($220 billion) over 32 years.
The Defence Ministry has not published its own cost estimatefor the lifetime of the four submarines, but has said it willtake up about 6 percent of the annual defence budget. In March,it put the cost of procurement at 31 billion pounds, plus almost4 billion already allocated to the design process. ($1 = 0.7583 pounds) (Reporting by Costas Pitas; Editing by Kevin Liffey)