British air strikes in Syria have killed or injured just seven Islamic State fighters since they began in December.
Estimates released by the Ministry of Defence show that by the end of January just four strikes by the Royal Air Force (RAF) resulted the jihadi group suffering casualties.
None of these strikes involved the much-lauded Brimstone missile, which Prime Minister David Cameron previously hailed as the kind of UK asset that would make a “meaningful difference” to the conflict.
Most of the RAF’s operations have targeted Islamic State infrastructure, including oil fields. The Mail also reports that a Ministry of Defence source said that strikes targeting militants were only carried out when there was no risk of civilian casualties.
Three fighters were killed in two separate attacks on Christmas Day. The first attack, on a position near Raqqa, killed one militant, while two more died in an attack on the Tabqa air base.
On January 11, a further two fighters were killed or injured in a Hellfire missile strike in Al Busayrah, while two more were targeted in a Paveway IV attack four days later.
A spokesman for the Ministry of Defence said: “We are playing a crucial role in a campaign that will take time and patience.
“Using the right weapon for each scenario, RAF jets have struck Daesh (ISIS) almost 600 times.
“In Iraq we have helped to drive them out of Sinjar and Ramadi. In Syria, we have severely weakened them by targeting their key infrastructure.”
Britain’s parliament voted to launch air strikes against Islamic State in early December following a concerted effort by Prime Minister David Cameron.
In 2013, parliament voted against launching similar strikes against the forces of Syria president Bashar al-Assad after allegations they had used chemical weapons.