The son of hate preacher Abu Hamza has left the UK to fight alongside rebel groups in Syria, it is believed.

Since making the 22,000-mile journey, Sufiyan Mustafa, 22, has played an active role in fighting and was involved in the siege of Aleppo, intelligence insiders claim.

It is unclear if Mustafa is fighting alongside Islamic State fighters or members of other rebel groups.

Hate preacher Abu Hamza's son, Sufiyan Mustafa, 22, has played an active role in fighting alongside rebel groups and was involved in the siege of Aleppo, intelligence insiders claim

Mustafa is the sixth of eight children fathered by Hamza, 58, an Egyptian-born hate preacher who is now serving a life sentence in a US prison for terror offences.

Mustafa's father, Hamza, rose to notoriety in the UK after becoming imam of the Finsbury Park mosque, in north London, in 1997

An intelligence insider told The Sunday People that Mustafa has no criminal record in the UK, but he 'has been part of military operations' in Syria.

The insider added: 'He has managed to stay a ghost since he set foot in Syria but it's thought he has been with rebels in the north.'

Experts believe that more than 800 Brits have flocked to Iraq and Syria to join 27,000 foreigners fighting for IS since violence broke out in 2011.

Mustafa's father, Hamza was jailed for life for terrorism offences during a trial in New York City in 2015, and has been serving his sentence in solitary confinement at a high security prison in Florence, Colorado.

Hamza was extradited to the US after the British government spent a decade trying to kick him out of the country.

He rose to notoriety in the UK after becoming imam of the Finsbury Park mosque, in north London, in 1997.

Hamza was jailed for life for terrorism offences during a trial in New York City in 2015, and has been serving his sentence in solitary confinement at a high security prison in Florence, Colorado.

One year later, in 1998, he helped organise hostage-taking of 16 mostly British tourists in Yemen. Three Britons and an Australian killed in rescue mission.

In 2000, he set up a terrorist training camp back in the US, in Bly, Oregon, sending volunteers and money to Afghanistan to support al Qaeda and the Taliban.

He then firmly placed himself on the national radar in 2001 after speaking out in support of Osama bin Laden following the September 11 attacks.

His current jail is known as the 'Alcatraz of the Rockies', due to its reputation as being inescapable.

It houses the most dangerous inmates in the US prison system and is believed to the world's most secure prison.

Two of Hamza's sons, as well as a stepson, have also been jailed for various offenses, including a bomb plot and a robbery.