Last month Davis admitted possession of a firearm and two charges of funding terrorism.

The charges dating back to 2013 and 2014 related to images with Davis' then-wife while he was in Syria and a failed bid to send him €20,000 (£17,400) via an unwitting courier.

He was arrested at Luton Airport last year after being deported from Turkey after serving a seven-and-a-half-year sentence for membership of IS.

Davis has always denied being connected with the Beatles cell - so-called because of their British accents - which tortured and beheaded Western hostages in Syria.

Two Beatles members, British nationals El Shafee Elsheikh and Alexanda Kotey, are serving life in US jails.

The third Beatle, Mohammed Emwazi, dubbed Jihadi John, was killed in a drone strike in 2015.

His legal team had claimed US authorities had accepted there was no fourth Beatle while the Court of Appeal noted any plan to extradite him there was "short-lived and discounted".

Davis witnessed 'atrocities' and achieved nothing significant, his barrister says

Making no reference to the Beatles, Mark Summers KC issued an apology to the Syrian people on Davis's behalf saying the defendant and those like him "did more harm than good".

Mr Summers said: "The reality he found when he arrived in Syria was profoundly different to anything he had ever imagined. What he thought he could achieve personally in a war zone transpired to be wholly and completely naive.

"Very little involved helping people of Syria. It involved most of the time in-fighting and schisms."

Having "misunderstood" his religious obligations to travel to Syria, Davis left in January 2014 having witnessed "atrocities" and achieved nothing significant, he said.

Mr Summers said: "He has a number of apologies to make through me today - the first is to the Syrian people. The presence of him, those like him and the groups he associated with there, caused more harm than good."

'You were not there for lawful purposes'

Judge Mark Lucraft KC jailed Davis for six years for the firearms offence and two years for terrorism funding to run consecutively.

The judge told him: "From the messages and images you sent to your wife it is clear you have been with fighters in Syria and that you were not there for lawful purposes. There are images of you in possession of firearms in November 2013."

Referring to the widely reported allegations for which Davis was not charged, the judge added: "I make it clear I am sentencing you for the offences on the indictment and for nothing else."

Judge Lucraft found Davis was not a dangerous offender, having taken into account the "passage of time" since he was in Syria.

However, Davis was told he will have to serve his entire custodial sentence and will be on licence for a further two years upon his release.

Davis posed with weapons

Davis left his home in London in 2013 and set off to join the conflict in Syria, having previously converted to Islam and spent time in the Middle East.

The evidence was largely uncovered from communications with his then-wife, mother-of-two Amal El-Wahabi, 36, who stayed behind in north London and who he enlisted in a plan to send him cash by hoodwinking her friend Nawal Masaad, 36, to act as courier on the promise of €1,000 (£870).

Ms Masaad was stopped at Heathrow Airport on 16 January 2014 as she was about to board a flight to Istanbul with €20,000 (£17,400) stuffed inside her tights, with the prosecution alleging the money, which was raised in the UK, was destined to support Davis's terrorist cause in Syria.

Following El-Wahabi's arrest uncovered a stash of terrorist propaganda said to have been left behind by Davis when he went to Syria.

On her mobile phone was a picture sent by Davis in November 2013 showing him with a man holding a Kalashnikov rifle in a Syrian wood.

Davis told his wife: "Don't show this to anyone but yuyu. [sic]. I mean it."

He sent another picture posing with 13 others in military-style clothes and holding up guns.

The court heard it was clear Davis had gone to Syria to fight under the black flag of Islamic State and he was preoccupied with martyrdom.

After the Old Bailey trial in 2014 El-Wahabi became the first person to be found guilty of funding terrorism in Syria and was jailed for 28 months, while Ms Masaad was cleared of wrongdoing.