The home secretary has warned he “will not hesitate” to block the return of a British teenager who left the UK to join Isis.

Sajid Javid said those such as 19-year-old Shamima Begum who had travelled abroad to engage with terror groups were “full of hate for our country”.

He added that if the heavily-pregnant Ms Begum did return to Britain, she could be prosecuted, despite protestations from her family, who argue she was just a child when she fled to Syria aged 15.

“My message is clear – if you have supported terrorist organisations abroad I will not hesitate to prevent your return,” Mr Javid told The Times.

“If you do manage to return you should be ready to be questioned, investigated and potentially prosecuted.”

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

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 Syrian camp, where she is being held alongside around 40,000 other family members of Isis fighters.

“I’m not putting at risk British people’s lives to go and look for terrorists or former terrorists in a failed state … actions have consequences,” Mr Wallace told the BBC.

“Some were groomed when they were young but are now adults – some of them are hardened fighters.”

While an official mission to retrieve Ms Begum from Syria looks unlikely to take place, questions have been raised over Mr Javid’s assertion she could be prevented from returning to the UK altogether.

The former independent reviewer of terrorism legislation, Lord Carlile, told the BBC that if Ms Begum did not have a second nationality she would have to be allowed to return to her homeland under international law preventing a person being made “stateless”.

Meanwhile, Richard Barrett, a former director of global counter-terrorism at MI6, suggested it would be “unreasonable” to expect the Syrian Defence Force to look after her indefinitely.

He also warned that summary execution is the “most likely outcome” for such captured foreign nationals who are handed over to Syrian or Iraqi authorities.

Ms Begum was one of three schoolgirls, along with Kadiza Sultana and Amira Abase, from Bethnal Green Academy in east London who left the UK in February 2015.

Another girl, Sharmeena Begum, also from Bethnal Green but not related to Shamima, had travelled to Syria two months earlier.

Ms Sultana was reported to have been killed in an airstrike in 2016, while Shamima Begum has said she recently heard second-hand the other two women may still be alive.

Support free-thinking journalism and attend Independent events

Debate has raged over whether the group, who were all either 14 or 15 at the time they left the UK, should be considered responsible for their actions or the victims of Isis “brainwashing”.

Hussen Abase, father of Amira Abase, has called for the women to be allowed to return home, insisting they had “made a mistake”.

“Before teenagers do anything, they don’t contemplate [what will happen],” he said: “They can be easily tricked … their age makes them vulnerable.”

Ms Begum, who recently fled the remaining pocket of Isis-held territory, said two of her children had died while she was in Syria and she wanted to return to the UK to ensure the safety of her third child.

Isis’s ‘scorched earth’ tactics damaged northern Iraq Show all 6 1 /6 Isis’s ‘scorched earth’ tactics damaged northern Iraq Isis’s ‘scorched earth’ tactics damaged northern Iraq Oil spills in Qayyarah, northern Iraq Wim Zwijnenburg/PAX Isis’s ‘scorched earth’ tactics damaged northern Iraq Plumes of black smoke from burning oil wells hung over Qayyarah for several months Wim Zwijnenburg/PAX Isis’s ‘scorched earth’ tactics damaged northern Iraq The burning of oil wells and oil spills have caused long term damage to the environment in Iraq Wim Zwijnenburg/PAX Isis’s ‘scorched earth’ tactics damaged northern Iraq Experts still do not know the extent of the damage from Isis's burning of oil wells and polluting of rivers Wim Zwijnenburg/PAX Isis’s ‘scorched earth’ tactics damaged northern Iraq Soil and water pollution is high in northern Iraq and impacting agriculture Wim Zwijnenburg/PAX Isis’s ‘scorched earth’ tactics damaged northern Iraq There are fears if environmental damage is not taken seriously agriculture in northern Iraq could be destroyed Wim Zwijnenburg/PAX

However, she has showed little remorse for her actions and appears indifferent to the group’s brutality, recalling she was “unfazed” by seeing a severed head in a bin.

“I don’t regret coming here,” she told The Times. “I’m not the same silly little 15-year-old schoolgirl who ran away from Bethnal Green four years ago.”

More than 400 British Isis fighters are already thought to have returned to the UK, with a report in 2017 warning many have since fallen off the radar of security services.

The government estimates roughly 900 people “of national security concern” travelled from Britain to Iraq or Syria to engage in the conflict, 40 per cent of whom have now returned, while a further 20 per cent have been killed.