Aine Davis, 38, was arrested on Wednesday evening after arriving into Luton airport on a flight from Turkey, according to BBC News.
A man alleged to be the fourth member of a terror cell known as The Beatles has reportedly been arrested in the UK on terror charges.
He was arrested in relation to offences under sections 15, 17 和 57 of the Terrorism Act, 2000.
Davis was arrested by officers from the Metropolitan Police’s Counter Terrorism Command and taken to a police station in south London, the BBC reported.
He is currently being held in police custody.
A Home Office spokesperson said: “We will always ensure the safety and security of the UK, and will not allow anything to jeopardise this.”
“We can confirm that a British national has been deported from Turkey to the UK, but it would be inappropriate to comment further while police enquiries are ongoing.”
Davis is said to have denied he was part of the Beatles cell – so nicknamed because of their English accents – which tortured and beheaded western hostages in Syria.
Cell ringleader Mohammed Emwazi, widely known as Jihadi John, was killed in a drone strike in 2015.
Londoner Alexanda Kotey was jailed in the US in April for his part in the torture and murder of American hostages.
His co-defendant, El Shafee Elsheikh, will be sentenced in August for his role in the plot.