Image copyright MOD

The UK has carried out more than 1,500 airstrikes against so-called Islamic State since it began its bombing campaign exactly three years ago.

Defence Secretary Sir Michael Fallon said it had made a major contribution to crippling IS and towards its collapse in Iraq and Syria.

The RAF has dropped about 3,500 bombs and missiles, which the BBC estimates has already cost £150m in munitions.

The MoD claims there is no evidence it is responsible for civilian casualties.

Missile costs

Extremists have lost considerable ground since they were first targeted by the RAF three years ago, more than 70% of the territory Islamic State (IS) once occupied in Iraq and 65% of the areas it once held in Syria.

After the US, Britain is the second-largest contributor to the coalition.

Each Brimstone missile costs more than £100,000 and the RAF has already fired more than 350, according to the BBC's estimate, defence correspondent Jonathan Beale said.

The RAF has targeted weapons stores, truck bombs, mortar teams, snipers and heavy machine-gun positions.

RAF Typhoon and Tornado jets and Reaper drones have flown more than 8,000 sorties carrying out strikes, surveillance and reconnaissance, and refuelling missions, the MoD said.

It said British forces destroyed 17 IS targets in Syria in one day last week.

'Tireless role'

Sir Michael said: "Britain has made a major contribution to the campaign that has crippled Daesh (Islamic State) since 2014, forcing this miserable cult from the gates of Baghdad to the brink of defeat in Raqqa.

"By air, land and sea UK personnel have played a tireless role in striking targets and training allies."

The RAF believes it has killed more than 3,000 extremists.

But the MoD said there was still "no credible evidence" that any civilian deaths had been caused, despite the fact that the bombing campaign intensified in the heavily populated cities of Mosul and now Raqqa over the past year.

Airwars, a group that monitors civilian casualties from international airstrikes in the region, has said it would be "statistically impossible" for the RAF to carry out hundreds of attacks without killing civilians.