The home secretary has been accused of “evading his duties” in order to “appear tough" after he announced he would not hesitate to block the return of a British teenager who left the UK to join Isis.

Sajid Javid said on Friday morning that heavily pregnant Shamima Begum and others who had travelled abroad to engage with terror groups were “full of hate for our country” and that he would prevent her from re-entering Britain – effectively making her stateless.

Lawyers and campaigners said blocking the 19-year-old’s return to Britain was “cruel and devoid of any moral obligations” and potentially a breach of international law.

The home secretary’s comments came after security minister Ben Wallace said he would not authorise a rescue operation to facilitate Ms Begum’s return to the UK.

The teenager is currently living in a Syrian camp, where she is being held alongside around 40,000 other family members of Isis fighters.

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

Human rights lawyer Shoaib Khan said it was unclear how the government could legally prevent Ms Begum’s return, as any attempt to permanently prevent her return while she remained a British citizen would be unlawful.

"Despite the rhetoric from the home secretary, which is clearly an attempt by him to just appear tough, it is unclear how the government can legally prevent her return,” he said.

“Her parents are of Bangladeshi origin, but there is no indication she is Bangladeshi. If she does not have Bangladeshi, or any other, nationality, then revoking her British citizenship would render her stateless, which contravenes international law.

“Also, while she is British, her baby, born anywhere in the world, would be British. Any attempt by the government to prevent that British baby entering the UK would obviously be almost certainly unlawful, whatever the mother’s actions have been before the birth.”

Mr Khan said that even if preventing her return was lawful, the UK should avoid the temptation to “dump unworthy citizens” on other countries or "disown individuals when they commit crimes”.

“As a government and as a nation, we must stop dealing with our undesirable citizens by washing our hands of them and forcing them on others. This not only makes a mockery of the legal system but is wholly irresponsible,” he added

Dr Zubaida Haque, deputy director of the Runnymede Trust, echoed his concerns, saying: “It's cruel and devoid of any moral obligations as Sajid Javid is deliberately trying to discharge himself and this country of any responsibility for this young vulnerable British woman.

“Morally speaking, Shemima Begum is a product of British society. Whether or not you committed a crime on this soil, if you’ve grown up here and you were radicalised here, you are a product of our society.

“It's also reckless because he's playing political football with her life (and her unborn child's life) and it's potentially against international law if he's intending to make her stateless.”

Maya Foa, director of human rights organisation Reprieve, argued that where British nationals detained in Syria were accused of committing crimes, they should be brought back to the UK to face trials in British courts.

“The UK can’t outsource British justice to the murderous regime of Bashar al Assad, the death rows of Iraq, or the legal black hole that is Guantanamo Bay,” she said.

Shadow home secretary Diane Abbott MP said Labour was not in favour of making people stateless.

But she added that if there were reasonable grounds to suspect that anyone who is entitled to return to the UK either committed or facilitated acts of terrorism, they should be “fully investigated and where appropriate prosecuted”.

It comes after Kurdish officials demanded that the UK fulfils its “moral and legal duty” to repatriate Ms Begum and other British Isis members detained in Syria.

Abdel Karim Omar, a Kurdish foreign affairs official, told The Independent thousands of detained Isis fighters, women and children were a “big burden”.

“They belong to 49 countries, and they don’t have documents and passports,” he added.