The British defence secretary, Sir Michael Fallon, is to announce that UK forces have arrived in the Middle East to help train moderate Syrian rebels engaged in the fight against Islamic State. Fallon is hosting a conference in London of defence ministers from the 67-member US-led coalition against Isis, and the defence secretary is keen to talk up the British contribution.



The conference is being held to discuss the next phase of the campaign against Isis as the group is squeezed in its Syrian headquarters in Raqqa and in its Iraqi headquarters in Mosul.



At a similar conference in Paris in October, Fallon announced that the UK would send about 20 trainers to help Syrian moderates with basic infantry skills, frontline medical treatment and identification of hidden explosive devices. His announcement on Thursday confirmed of their arrival.



In a statement before today’s meeting the defence secretary said: “Daesh [the government’s name for Isis] is being taken on in eastern Mosul. Last week we opened up a second front around Raqqa. Daesh is losing ground, finance and fighters … In 2017, we must maintain momentum to deal these terrorists a decisive blow.”

In spite of the push on Mosul and Raqqa, Isis fighters managed a success this week, temporarily retaking Palmyra in Syria, a development that highlighted how overstretched the forces of the Syrian president, Bashar al-Assad, have become. Most of Palmyra has since been reported to have been retaken. The Iraqi army’s push on Mosul has also recently stalled in the face of strong Isis resistance.



The UK already has a modest force of 500 infantry in Iraq to help train the Iraqi army. The Ministry of Defence says British troops have trained more than 31,000 Iraqi and Kurdish fighters.



The extra 20 trainers have been sent specifically to train Syrian groups, a controversial issue in the past, given the difficulty of distinguishing “moderate” rebels from more extreme groups. Fallon stressed in October that they would be thoroughly vetted to ensure that the UK was not training Islamist factions.



The US has special forces on the ground in Syria helping Kurdish troops and Syrian rebels who have surrounded Raqqa. Officially the UK has no troops in Syria, though some are known to have gone at least on reconnaissance trips.



The Syrian Democratic Forces, classified by the UK as moderates, said they had started a new phase of an operation to isolate Raqqa with the help of the airstrikes from the US-led coalition, which has carried out 300 raids since November. About 70% of UK airstrikes since June have been in support of the Iraqi army and Kurdish fighters trying to retake Mosul.



Fallon will also announce that the UK is to send more intelligence specialists to help sift through the thousands of documents expected to be seized as Mosul and Raqqa fall, in the hope of learning more about the internal structures of Isis, any planned overseas terrorist plots and the identities of financiers.



The fall of Manbij in Syria earlier this year provided the US-led coalition with a trove of documents that allegedly pointed to plots in Europe, though not specifically against the UK.



The conference in London marks the last visit to the UK by Ash Carter in his capacity of US defence secretary before the Trump administration takes over on 20 January.

