One of Saddam Hussein's former palaces used by the Islamic State as a major training base for foreign fighters has been bombed by the RAF, the Ministry of Defence said.
The Mosul palace built by the former Iraqi dictator was attacked in a joint coalition operation on Monday.
The attack followed extensive surveillance which established that the terrorist group, also known as Daesh, were using the sprawling grounds as a headquarters and training centre for foreign terrorist recruits.
The complex, sat in a large secure compound next to the River Tigris, included the main palace building, used as an accommodation and meeting venue by the terrorists, as well as a number of more discreet outbuildings used for command and control, training, internal security and repression.
The Ministry of Defence said: "The British contribution was a pair of Tornados, armed with the largest guided bombs in the RAF's inventory, the 2000lb Enhanced Paveway III, which were used to target first the headquarters buildings, then a security centre.
"Initial analysis indicates that the coalition mission was successful."
Defence Secretary Michael Fallon said: "Daesh has been losing followers and territory for months, and emphatic strikes like this show that we and the coalition will not waver.
"Daesh fighters, both foreign and home-grown, can see that they are targets inside this cult."
Mr Fallon announced that additional UK troops will be deployed to Iraq to support the military effort against Daesh later this month.
The trainers will be based at the Al Asad airbase, where they will provide counter improvised explosive device (c-IED), first aid and infantry skills training.
During a visit on Tuesday to RAF Akrotiri, from where Tornado and Typhoon aircraft are flying daily missions against Daesh in Syria and Iraq, Mr Fallon insisted the UK is not holding back from its international commitments following the EU referendum vote.
He said: "These troops will bolster a campaign that has Daesh on the back foot.
"The uplift underlines that Britain is stepping up, not stepping back from our international commitments, following the EU referendum."
UK troops have helped to train more than 21,000 Iraqi forces and carried out over 900 strikes, alongside the coalition.
The UK Government also recently delivered around £1.4 million worth of machine gun and sniper ammunition to the Kurdish Peshmerga who are battling Daesh in the north of Iraq.