RAF Typhoon jets have operated alongside French aircraft in a combined operation on an underground arms cache in Syrian territory operated by the IS group, according to the UK's MoD.
The site, located using intelligence, was assessed as housing weapons and explosive materials, the statement said, and was located in mountains just above Palmyra in Syria's central region.
"The RAF jets utilized Paveway IV guided bombs to strike a several entry passages down to the facility... preliminary assessments suggest the strike was effective," officials stated.
There was no sign of any civilian impact in the operation on Saturday evening and all the aircraft made a safe return, the MoD added.
The British jets were assisted by a Voyager tanker plane.
The Islamic State group - alternatively referred to as the so-called Islamic State - established jihadist rule over parts of Syria and Iraq before its territorial defeat in 2019.
"This strike shows British leadership, and resolve to work closely with allied nations, to eradicate any revival of the terrorist group and their harmful and extremist ideologies in the area," UK Defence Secretary the minister remarked.
RAF aircraft have conducted surveillance missions over Syrian airspace to "prevent any attempted comeback" of Islamic State following its routing at the climactic battle in Baghuz in 2019, the ministry said.
"I extend gratitude to every member of the UK armed forces who took part in this strike for their skill and their bravery," he added. "Including them were a great many UK service members stationed over Christmas and New Year. This mission, to take out militants who threaten our security, demonstrates how UK forces are ready to step up, throughout the year, protecting the UK domestically and strong abroad."
Last December, the American forces conducted what it termed a "major assault" on Daesh sites in the country, subsequent to an ambush killed two US servicemembers and a civilian interpreter in Palmyra.
The United Nations says Islamic State still maintains between 5,000 and 7,000 combatants in Iraq and Syria.
