Hundreds of Britons caught trying to join jihadist groups in Syria

Mr Hammond’s comments, which were made during a visit to southern Turkey, come just days after MP Keith Vaz claimed that 14 of the 17 British children on the run in Syria are from Bradford.

Mr Hammond said an estimated 800 UK citizens had entered Syria in the past four years, with around half thought to still be in the country.

Mr Hammond said the British and Turkish intelligence services had managed to stop hundreds more joining them, stopping some leaving the UK and others as they arrived in Istanbul - a key staging point on the route to Syria.

Mr Hammond said: “Approximately 800 Brits have been to Syria, of whom half are still there. But on top of that 800, we have stopped another 600.”

He said the growing success of the authorities in preventing foreign fighters reaching IS in its Syrian stronghold of Raqqa was adding to the pressure the group was facing from western air strikes.

He said: “There is evidence (IS) is finding it difficult to recruit to the brigades in Raqqa because of the high attrition rate of foreign fighters.

“Not just those targeted in UK drone strikes, but US strikes against prominent targets including foreign fighters.”

“Generally they are very stretched now - their manpower on the ground in relation to the territory they’re holding is very thin.”

Earlier this week Keith Vaz MP, chairman of the Home Affairs Select Committee, quizzed two representatives from Bradford’s Islamic community over their knowledge of two fleeing families from the city, including three sisters, Zohra, Khadija and Sugra Dawood, who left with their nine children.

Mr Vaz said he was puzzled the pair knew so little about radicalisation in their community, even though they told the committee they deal with a lot of British Muslims.

He said: “The last group went in August 2015 and before that in June 2015, but you don’t know any of these families and they’ve had no contact with you? Even though 90 per cent of the British children in Syria are actually from Bradford.”

Zulfiqar Karim, Senior Vice President, Bradford Council for Mosques, said: “We found that both of those families, and this is what we are hearing, is these were breakdowns in families.

“There was no Islamic ideology, they did not belong to any one radical imam that’s convinced them. Our understanding is there was a breakdown of marriage and these families were looking for an alternative, and they found an alternative overseas.”

The Dawood sisters disappeared from their homes with their nine children last June, and are feared to have travelled to Syria. Despite the efforts of authorities in the UK, nothing has since been heard of their whereabouts.

According to Balaal Hussain Khan, a lawyer acting for the fathers of the missing children, one of them has now gone to live with relatives in Pakistan because he is struggling to cope with life without his children in Bradford.

He said: “He has struggled to handle everything. He had a heart attack as well. He said to me ‘I’m in my house and it is filled with memories of my children and I can’t handle it.”

The number of girls and women travelling from the UK to Syria is on the rise after new figures revealed 56 are thought to have fled to the war-torn country last year.

Counter-terrorism officers said they were “deeply concerned” about the number of cases as many women were unaware that they will probably never be able to return home.

Figures released in July showed 43 females were thought to have fled from the UK to Syria in the previous 12 months.

The figures were disclosed as a short film was released featuring three female Syrian refugees talking about the realities of life in their home country.