The RAF has killed 330 Isis extremists during airstrikes in Iraq, according to the Defence Secretary.
Michael Fallon said the figure was an estimate covering the period September 2014 to August this year.
Answering a parliamentary question from Brighton MP Caroline Lucas, he said: “This figure is highly approximate, not least given the absence of UK ground troops in a position to observe the effects of strike activity.
“We do not believe there have been any civilian casualties as a result of UK strike activity.”
MPs overwhelming approved air strikes against Isis fighters in Iraq last September, with the Conservatives, Liberal Democrats and Labour party all supporting the action.
But Parliament rejected any potential UK military action against President Bashar al-Assad in Syria in September 2013, after his suspected chemical weapons attack on its people in which hundreds were reported to have died.
In July, Mr Fallon said the UK should again consider air strikes against Isis in Syria, but that no action would be taken without a vote in Parliament.
Prime Minister David Cameron has indicated the UK should extend its military involvement against Isis from Iraq to Syria, but new Labour leader Jeremy Corbyn opposes intervention, believing it could risk creating more problems for people in Syria and that the UK should instead try to work for peace in the region.
Writing in the Observer last week, Mr Corbyn said: “The Prime Minister will soon again be asking us to bomb Syria. That won’t help refugees, it will create more.
“Isis is utterly abhorrent and President Assad’s regime has committed appalling crimes. But we must also oppose Saudi bombs falling on Yemen and the Bahraini dictatorship murdering its democracy movement, armed by us.
“Our role is to campaign for peace and disarmament around the world.”
Earlier this month, an RAF drone strike killed two suspected British jihadis, Reyaad Khan and Ruhuk Amin, in the Isis stronghold of Raqqah in Syria.
Mr Cameron said the attack had been justified on the grounds of self-defence, while Mr Corbyn said the strike was "legally questionable".
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