BRITAIN has been told to brace for civilian casualties, radicalisation and rising numbers of refugees after MPs backed air strikes in Syria last night despite growing public opposition.

Prime Minister David Cameron dragged Britain into a fourth disastrous military intervention in 15 years with the help of Lib Dem and Labour hawks.

His emergency motion to extend British air strikes from Iraq to Syria garnered the support of 397 MPs — 67 of them Labour — while 223 voted No.

The PM insisted the shadow of Iraq, Afghanistan and Libya should not stop air strikes against the “medieval monsters” of Islamic State (Isis) in Syria.

“This is not 2003,” he said, recalling the year Tony Blair duped MPs into declaring war on Iraq. “We must not use past mistakes as an excuse for indifference or inaction.”

But Labour leader Jeremy Corbyn said the spectre of those “disastrous wars” hung over a decision which would have “unintended consequences.”

He said: “To oppose another reckless and half-baked intervention isn’t pacifism. It’s hard-headed common sense.

“It’s wrong for us here in Westminster to see a problem, pass a motion and drop the bombs pretending we’re doing something to solve it.”

With British Tornado jets, which have been bombing Isis bases in Iraq for over a year, already stationed in the region, they can begin unleashing “brimstone” missiles on targets in Syria immediately.

Mr Corbyn challenged the PM’s claim that superior RAF technology would save lives, telling him that more bombing “will kill innocent civilians.”

The Labour leader also raised concerns over the absence of ground troops, a diplomatic roadmap to peace or a plan to deal with refugees fleeing British bombing.

“It’s become increasingly clear that the Prime Minister’s proposal for military action simply doesn’t stack up.”

Mr Cameron conceded it was not an “ideal situation,” but insisted the RAF “do serious damage to Daesh’s [Isis’s] ability right now to bring terror to our streets.”

The PM also shrugged off warnings from the Muslim Council of Britain and others that bombing could increase radicalisation in Britain, claiming: “We are engaged in a defence of Islam.”

He failed to convince senior back-bench Tories, such as foreign affairs select committee member John Baron and defence select committee chairman Julian Lewis.

They were among 110 MPs from six different parties who signed up to a wrecking amendment against air strikes yesterday morning, which pointed out that 10 countries are already bombing Syria.

The amendment was defeated 390-211.

“Too many aircraft are already chasing too few targets,” warned Mr Baron.

Party grandees Alan Johnson and Margaret Beckett came out in favour of bombing, along with former paratrooper Dan Jarvis, who argued that Isis “are the fascists of our time.”

And shadow foreign secretary Hilary Benn won applause from the Tory benches as he bear Mr Cameron’s war drum, rallying his own MPs to give solidarity to the French Socialist Party, whose President Francois Hollande has asked fellow EU states to join France’s air strikes.

He blustered: “I say the threat is now and there are rarely, if ever, perfect circumstances in which to deploy military forces.”

Before the debate had even begun, Mr Cameron faced criticism for stopping the debate from continuing today.

Mr Corbyn said it was because the PM knew “public opposition to his ill-thought-out rush to war is growing — and wants to hold the vote before it slips from his hands.”

The Stop the War Coalition staged a snap protest outside Parliament last night — the second in as many days.

TUC general secretary Frances O’Grady also condemned the vote, saying: “Everyone shares the horror felt at the attacks carried out in Paris, Mali and elsewhere and at the suffering of people living under Isis rule. But the government’s case for air strikes in Syria remains unproven.

“Ministers have failed to counter the concern that, without a clear plan for a sustainable settlement led by the UN and the region, bombing would only make matters worse.”