David Lammy's speaking after Labour leader Jeremy Corbyn emailed members of his party, who are divided on the issue, to find out their opinion.
Jeremy Corbyn has urged against airstrikes against IS in Syria, arguing that it will encourage more terror attacks against Britain in revenge.
Members of Jeremy Corbyn's cabinet have expressed their support for Syrian airstrikes, however, and it's been reported that it's possible there could be front-bench resignations if Mr Corbyn orders the party to vote against them.
Mr Lammy agreed with his leader after a debate on the issue on Friday, however he said he believed Labour MPs must be allowed to vote in accordance with what they thought rather than a collective party line.
Given its number of MPs, if Labour takes a group decision on airstrikes as a party that will have a significant affect on the outcome of a vote on whether to conduct.
Prime Minister David Cameron, who has led calls to extend IS bombing from Iraq to Syria, has said they will make Britain more safe by helping to eliminate the militant group in what he claims is their headquarters.
Mr Cameron has also argued it is the right thing to do and Britain's duty to bomb IS in Syria, given recent terror attacks in Tunisia and Paris as well as other atrocities committed by the militants.
David Lammy said: "I would've been prepared to sanction bombing if the arguments had been clear, the strategy had been clear, I'd been clear on the aftermath, and I was convinced that we would not be generating a new generation of radicalised jihadists who would come and bomb us on our streets - and I'm afraid I was not convinced.
"We have Russia flying planes, we have the French flying planes, we have the Americans flying planes, we have the Turkish. It's not entirely clear what it would add.
"When you're fighting what is in the end an ideology, when you're fighting apparently a war on terror that can go on with no end in sight, this is quite quite different to eradicating a fascism that we saw in the Second World war.
"It persuades other young people to either join the cause or form a different cause, because inevitably civilians will be killed and people will perceive it as Britain killing those civilians."