A British man, accused of trying to join Isis in Syria, has arrived in the UK after being deported from Turkey.

The 26-year-old man, who has not been officially named, was on a flight that landed at Heathrow Airport on Thursday afternoon.

A spokesperson for the Metropolitan Police said: “He was arrested on suspicion of preparation of terrorist acts under section 5 of the Terrorism Act 2006. The arrest is Syria-related.”

The man remains in custody as the investigation continues.

He was one of several alleged British Isis supporters held in Turkish prisons, where Aine Davis – a member of “The Beatles” terror cell – was jailed after a 2017 trial.

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 offence of preparing terrorist acts is levelled against people accused of travelling to join Isis, as well as for those plotting attacks.

Turkey announced the deportation earlier in the day, alongside that of several German Isis suspects.

Ankara has, this week, accelerated a push to deport suspected foreign Isis fighters held in prison to their respective countries, a move that dovetails with Donald Trump’s demands that European countries take back and try militants caught in the battlefields of Syria and Iraq.

Kurdish forces that were backed by the US-led coalition – to push Isis out of its “caliphate” – are holding tens of thousands of people, caught fleeing the terrorist group’s territories, including foreign fighters from around the world.

The Syrian Democratic Forces (SDF) has warned that it may not be able to secure the camps if Turkey continues an advance into northern Syria, and said it was the “moral and legal duty” of the UK and other countries to repatriate their citizens.

The British government has dramatically increased its use of controversial citizenship deprivation powers in attempts to prevent Isis members from returning to the UK.

Only one in 10 of the around 400 suspected jihadis who have returned to Britain since 2014 have been prosecuted.

The government has repeatedly refused calls to repatriate British men, women and children held in Syria, arguing it is too dangerous for officials to undertake the task.

But it cannot prevent UK citizens from seeking consular assistance if they manage to leave the war-torn country.

Donald Trump claims remaining Isis fighters 'will escape to Europe' during Turkish-Syria conflict

The Home Office has previously confirmed that British nationals have the right to return to the country but they will be investigated by police and authorities may use a “range of tools” to control and monitor them.

Turkey’s interior ministry said it would be sending a total of 23 foreigners to their countries in the following days.

An American, seven Germans, an Irish woman, and a Belgian were among those to be deported.

“Countries can’t just revoke the citizenship of such ex-terrorists and expect Turkey to take care of them; this is unacceptable to us and it’s also irresponsible,” interior minister Süleyman Soylu told reporters last week. “Turkey is not a hotel for foreign terrorists.”

One suspected Isis fighter, a US citizen of Jordanian origins, has been stuck on the border between Turkey and Greece, which has refused to allow him entry. He was deported to the US on Thursday.

“Necessary procedures have been launched to send the foreign terrorist fighter stuck in the buffer zone to the US, upon a US commitment,” Turkey’s state-funded Anadolu news agency reported.

The wave of deportations comes after a White House meeting on Wednesday between Turkish president Recep Tayyip Erdogan and Mr Trump, who has hectored European leaders for failing to take back nationals who joined Isis in recent years.

Lisa Smith, an Irish woman who allegedly joined Isis, and her two-year-old daughter, are set to be deported to Ireland.

Turkey says it has captured about 1,200 foreign nationals suspected of having links to Isis.

Both Turkey and the US have complained about Europe’s reluctance to take back their nationals.

“We will continue sending them, so if they take them or do not take them doesn’t really concern us,” Mr Erdogan said on Tuesday before leaving for the US.