Ministers would be guilty of “rendition” if the government brought British Isis fighters and their families back from Syria against their will, the defence secretary Ben Wallace has claimed.

Appearing to harden the government’s stance towards against repatriating jihads from refugee camps and prisons in the region, Mr Wallace also claimed there may not be enough evidence in certain cases to convict them in a court of law.

Kurdish officials have demanded the UK fulfils its “moral and legal duty” to repatriate Shamima Begum and other British Isis members detained in war-ravaged Syria.

They are being held indefinitely in squalid camps where children including Begum’s baby have died, and rampant extremism could be creating the conditions for an Isis resurgence.

US defence secretary Mark Esper has urged Boris Johnson’s government to take back jihadis held in the region, where he claimed there were more than 2,000 foreign fighters detained after the fall of Isis’s “caliphate”.

Timeline of the Isis caliphate Show all 19 1 /19 Timeline of the Isis caliphate Timeline of the Isis caliphate ISIS began as a group by the merging of extremist organisations ISI and al-Nusra in 2013. Following clashes, Syrian rebels captured the ISIS headquarters in Aleppo in January 2014 (pictured) AFP/Getty Timeline of the Isis caliphate Abu Bakr Al-Baghdadi declared the creation of a caliphate in Mosul on 27 June 2014 Timeline of the Isis caliphate Isis conquered the Kurdish towns of Sinjar and Zumar in August 2014, forcing thousands of civilians to flee their homes. Pictured are a group of Yazidi Kurds who have fled Rex Timeline of the Isis caliphate On September 2 2014 Isis released a video depicting the beheading of US journalist Steven Sotloff. On September 13 they released another video showing the execution of British aid worker David Haines Timeline of the Isis caliphate The US launched its first airstrikes against Isis in Syria on 23 September 2014. Here Lt Gen William C Mayville Jnr speaks about the bombing campaign in the wake of the first strikes Getty Timeline of the Isis caliphate Isis militants sit atop a hill planted with their flag in the Syrian town of Kobani on 6 October 2014. They had been advancing on Kobani since mid-September and by now was in control of the city’s entrance and exit points AFP/Getty Timeline of the Isis caliphate Residents of the border village of Alizar keep guard day and night as they wait in fear of mortar fire from Isis who have occupied the nearby city of Kobani Getty Timeline of the Isis caliphate Smoke rises following a US airstrike on Kobani, 28 October 2014 AFP/Getty Timeline of the Isis caliphate YPG fighters raise a flag as they reclaim Kobani on 26 January 2015 VOA Timeline of the Isis caliphate Isis seized the ancient Syrian city of Palmyra on 20 May 2015. This image show the city from above days after its capture by Isis Getty Timeline of the Isis caliphate Kurdish forces are stationed on a hill above the town of Sinjar as smoke rises following US airstrikes on 12 November 2015 AFP/Getty Timeline of the Isis caliphate Kurdish forces enter Sinjar after seizing it from Isis control on 13 November 2015 AFP/Getty Timeline of the Isis caliphate Iraqi government forces make the victory sign as they retake the city of Fallujah from ISIS on 26 June 2016 Getty Timeline of the Isis caliphate Iraqi forces battle with Isis for the city of Mosul on 30 June 2017 AFP/Getty Timeline of the Isis caliphate Members of the Iraqi federal police raise flags in Mosul on 8 July 2017. On the following day, Iraqi prime minister Haider Al Abadi declares victory over Isis in Mosul Getty Timeline of the Isis caliphate Members of Syrian Democratic Forces celebrate in Al-Naim square after taking back the city of Raqqa from Isis. US-backed Syrian forces declare victory over Isis in Raqqa on 20 October 2017 after a four-month long campaign Getty Timeline of the Isis caliphate Female fighters of the Syrian Democratic Forces celebrate in Al-Naim Square after taking back the city of Raqqa from Isis. US-backed Syrian forces declare victory over Isis in Raqqa on 20 October 2017 after a four-month long campaign AFP/Getty Timeline of the Isis caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria in January 2019 They were among the last civilians to be living in the ISIS caliphate, by this time reduced to just two small villages in Syria’s Deir ez-Zor Richard Hall/The Independent Timeline of the Isis caliphate Zikia Ibrahim, 28, with her two-year-old son and 8-month-old daughter, after fleeing the Isis caliphate, on Saturday 26 January 2019 Richard Hall/The Independent

But the government has so far rebuffed the calls, instead dramatically increasing its use of controversial powers to deprive extremists of their British citizenship to prevent any return to the UK.

Asked on the fringes of the Conservative Party conference what the government should do with captured jihadis from the UK, Mr Wallace insisted the government does not provide consular services in Syria.

“I know people go around refugee camps and prisons but they are journalists and aid workers. When you go down there as a member of the crown you become a target,” he said.

Mr Wallace continued: “People say ‘bring them back, put them on trial’. If I bring someone back against their will, I’m guilty of rendition. Under international law, I can’t just swoop into a country and grab someone ... unless they come under extradition. We don’t have an extradition treaty with the Syrian regime, not surprisingly.

“Therefore it’s not as straightforward as just flying into those countries and picking people up, because the first thing that will happen when they do come back for trial, the defence will be – we won’t be able to convict them.”

Legal experts questioned Mr Wallace’s claim over rendition, which commonly refers to the extrajudicial transfer of people from one state to another for interrogation and potential torture.

The US government and Kurdish authorities holding the Isis suspects have said they would support repatriations from Syrian camps to Britain, where normal legal processes would be followed.

Maya Foa, director of the Reprieve legal charity, said Mr Wallace’s rendition argument was the “the latest in a string of different excuses” the government has used to justify its inaction.

“Each time one of these flimsy excuses is revealed as bunk, the government draws another disingenuous card from the pack,” she told The Independent.

Jeremy Hunt says British officials didn't rescue Shamima Begum's baby because it was too dangerous

“The US has asked time and time again that the UK repatriate its citizens from camps in northeast Syria. Rhetorical sleight of hand must not be allowed to distract from the disastrous lack of sensible policy in this area.”

Several other countries have already taken their citizens out of Syrian Democratic Forces custody, including the US, Belgium, Italy, Morocco and Bosnia.

A number of captured UK jihadis, including Begum and members of “the Beatles” Isis cell, have voiced wishes to return to Britain even if they are jailed.

Mr Wallace claimed that some evidence held on Isis jihadis could not be presented in British courts as the intelligence belongs to other nations.

The cabinet minister added: “If we could bring some of these people, and I was prepared to put at risk British soldiers and civil servants to wander around those kind of camps finding them – we could do all of that, but we might not be able to convict them.

“Then let’s see how many people want those people living next door to them. That is a big question.”

A suite of strengthened terror laws came into effect earlier this year, and Isis members can also be charged with pre-existing offences including membership of a proscribed organisation.

A Supreme Court case heard that there was enough evidence to prosecute alleged Isis “Beatles” Alexanda Kotey and El Shafee Elsheikh in Britain, after Sajid Javid suggested there was not.

Mr Wallace said when it comes to the children of Isis fighters and their wives “it is of course difficult”.

“We are compassionate to the needs of some of these children,” he said. “What we have done in the past is when those children have got to the Turkish border or to Turkey, they are given consular assistance that we provide in Turkey and those children do get the benefit of the UK.

“But the policy of providing consular services in Syria has been consistent for a long time, we won’t provide consular services.”

Some nations, including Australia, have facilitated the transfer of people to countries outside Syria where they have consular services.

Ken Clarke and former defence minister Tobias Ellwood are among the politicians raising concern over the government’s policy.

Mr Ellwood told The Independent the detention of thousands of jihadis and their families in Syria was creating conditions for an Isis resurgence.