A British man accused of being part of an Islamic State (IS) kidnap-and-murder cell known as the "Beatles" appeared in court in London on Thursday on terrorism charges after returning to the UK.

The Metropolitan Police said Thursday that 38-year-old Aine Davis had "been charged with various terrorism offenses following an investigation by the Met's Counter Terrorism Command".

Davis appeared at Westminster Magistrates' Court in central London on Thursday morning flanked by two suited police officers.

Sporting a short beard and wearing a grey T-shirt, Davis spoke only to confirm his full name and that he was of no fixed abode.

Chief Magistrate Paul Goldspring remanded him in custody, saying that there would be no bail application due to the likelihood that he might abscond and his "propensity to travel on forged documents".

He faces three counts under terrorism laws, two related to terrorism fundraising and one related to possessing a firearm.

Davis was allegedly a member of the IS cell that held dozens of foreign hostages in Syria between 2012 and 2015 and was known to their captives as the "Beatles" because of their British accents.

He converted to Islam and adopted the name Hamza, the Criminal Prosecution Service said in a statement. It said he had been deported to the UK by Turkish authorities.

The Met, which leads anti-terror investigations in the UK, said they arrested Davis after he landed at Luton airport on a flight from Turkey.

Goldspring said in court that if Davis is convicted, he will face "years, not months" in prison.

The case was referred to the Crown Court, with the next pre-trial hearing set for September 2 at the Central Criminal Court, known as the Old Bailey.

The four members of the "Beatles" are accused of abducting at least 27 journalists and relief workers from the United States, Britain, Europe, New Zealand, Russia and Japan.

Two have already been brought to justice and one was killed.

They were all allegedly involved in the murders of American journalists James Foley and Steven Sotloff, as well as aid workers Peter Kassig and Kayla Mueller.

The quartet allegedly tortured and killed the four American victims, including by beheading, and IS released videos of the murders for propaganda purposes.

Alexanda Kotey, a 38-year-old former British national extradited from the UK to the US in 2020 to face charges there, pleaded guilty to his role in the deaths last September and was sentenced to life in prison in April.

El Shafee Elsheikh, 34, another former British national also extradited to the US at the same time, was found guilty of all charges in April, and will be sentenced next week.

Wife jailed

The other "Beatles" executioner, Mohamed Emwazi, was killed by a US drone in Syria in 2015.

Elsheikh and Kotey were captured in January 2018 by a Kurdish militia in Syria and turned over to US forces in Iraq before being sent to Britain.

They were eventually flown to Virginia in 2020 to face charges of hostage-taking, conspiracy to murder US citizens and supporting a foreign terrorist organisation.

Davis served a seven-and-a-half-year sentence in Turkey for membership in the terrorist group, according to reports.

In 2014, his wife Amal El-Wahabi became the first person in Britain to be convicted of funding IS jihadists after trying to send 20,000 euros -- worth $25,000 at the time -- to him in Syria.

She was jailed for 28 months and seven days following a trial in which Davis was described as a drug dealer before he went to Syria to fight with IS.

A warrant was issued in 2015 at Westminster Magistrates' Court for Davis's arrest over possession of a firearm for suspected terrorist purposes between 2013 and 2014, the CPS said.

The arrest warrant also referred to requesting and passing on money while knowing or suspecting it would be used for "the purposes of terrorism", the CPS said.