SAS troops took part in the mission to hunt down and kill Islamic State commander Abu Bakr al-Baghdadi, the Mirror can reveal.
A small number of men joined the US-led attack on the terror chief’s hideout in northwest Syria after tracking him for a fortnight.
Once at the target, two landed to dispatch soldiers and third hovered above them with their guns trained on the compound.
Al-Baghdadi is said to have fled into a tunnel before setting off an explosive vest, killing himself and three of his young children. A US AC 130 “flying gun” and Reaper drone armed with 500lb bombs then flattened the den after the troops had withdrawn.
A source said last night: "The UK has an exchange deal which is long standing with the US special operations in Iraq, which mounted the mission.
"No doubt lessons were learned from previous operations."

It emerged yesterday evidence gathered during the mission may help prosecutions of IS terrorists, such as British "Beatles" Alexanda Kotey and El Shafee el-Sheikh.
A UN team investigating crimes committed by the organisation said “some of the information would be definitely relevant” to their probe.
The MoD refused to comment on SAS involvement in the al-Baghdadi raid.

Defence Secretary Ben Wallace said: "I welcome the action that was taken. The world will not miss al-Baghdadi."
Prior to his death, a $25million bounty was placed on Baghdadi 's head.
He became active in al-Qaeda following the US-led invasion of Iraq in 2003 and spent time in the infamous Abu Ghraib detention centre.