RAF and other coalition planes last month engaged in the biggest air raids against Isis in two years, in a 10-day mission that attacked up to 100 cave hideouts in Iraq and is likely to have caused dozens of casualties.
The attacks concluded on 22 March, the Ministry of Defence said.
British and other nations’ forces are fighting an estimated 10,000 Isis guerrilla fighters operating in Syria and Iraq, nearly seven years after the war against the terror group began.
Air Commodore Simon Strasdin, who leads the UK air attacks, said he “could not give an exact timeline” for when the long-running war would end but insisted it would be “winnable through the Iraqis being able to stabilise their country”.
Iraq has been embroiled in conflict almost continually since the 2003 invasion by US, UK and other international forces, a situation that developed further with the emergence of Isis in the country and neighbouring Syria from around 2013.
The exact number of casualties in the latest operation is unknown; the cave complexes remain to be cleared out by Iraqi ground forces.
Strasdin said: “We went after, as a coalition, a number of these targets every night for circa 10 days.” It amounted “to between 50 and 100 of the targets and complexes”.
It is probable that dozens died. Strasdin predicted that the UK would be involved in operations during 2021 that would lead to more people killed than the 67 whom the UK said died fighting British forces during 2019 and 2020.
Isis fighters have been hiding out in the remote Makhmur mountains area – which lies between the Iraq government zone of control in the south and the Kurdish-run north – in a series of modified limestone caves that UK defence sources said were at least three miles from civilian sites.
The attacks on the cave complexes are understood to have taken months of planning as coalition forces sought to first find and then locate the hideouts. “This was many, many months of building understanding and intelligence,” Strasdin said.
Britain joined the US and dozens of other countries in attacking Isis from the air while relying on local ground forces. Early in 2019 the terror group lost the last of its territory, leading to speculation as to when the war would end.
At one point between late 2019 and early 2020 air raids and drones strikes by the RAF ground to a halt. But the latest raids show the conflict is far from over, even as those involved argue that the end of the war remains relatively close.
Chris Coles, from Drone Wars, which tracks air and drone strikes by British forces, said that the heavy bombardment in northern Iraq was “perhaps the first indication” of a constant campaigning strategy outlined by the UK government in last month’s integrated review of defence and foreign policy.
“With few boots on the ground there is almost no pressure to bring military interventions to an end and so we are likely now to see British aircraft and drones engage endlessly in sporadic bouts of bombing with almost no visibility of the consequences for those on the ground,” he added.
The RAF used Typhoon jets during the operation, targeting the caves with Paveway bombs, and used Storm Shadow cruise missiles for the first time in two years. Separately, on 4 April, an RAF Reaper drone struck in Syria for the first time in almost two years, aiming at a group of Isis members.