A British jihadi who posed with the severed heads of Syrian soldiers and faked his own death to sneak back into the UK has been jailed for 12 years.

But Imran Khawaja - who spent six months in Syria alongside insurgents linked to terror group Islamic State - has appealed to other young British Muslims not to make the same mistakes he did.

He acted as a frontman for Rayat Al Tawheed, posting dozens of photos and videos online and boasting of his weapons training and exploits on the battlefield.

He also encouraged other young men and women to become jihadis and travel to the region.

During a two-day sentencing hearing at Woolwich Crown Court in south east London, Khawaja's defence team appealed to the judge, Mr Justice Baker for leniency, claiming the 27-year-old was a "psychologically vulnerable" young man who bitterly regretted his actions.

But prosecutor Brian Altman QC said Khawaja had featured in some disturbing footage of decapitated Syrian government soldiers.

In one video sequence, played before a hushed court, Mr Altman said Khawaja could be seen picking up severed heads from the back of a flatbed truck and saying: "Heads. Kuffar (non-Muslims) Disgusting."

Mr Altman said: "His attitude is quite clearly contemptuous. There is no sign of compulsion or revulsion."

At a court hearing last month, the former security guard pleaded guilty to preparing acts of terrorism, attending a terror training camp in Syria and receiving weapons training.

He was sentenced today alongside two other men, his cousin Tahir Bhatti, who pleaded guilty to assisting an offender and his friend Asim Ali, who admitted terrorism funding.

Bhatti, a taxi driver, was persuaded to travel to Bulgaria last June to pick up Khawaja and help smuggle him back into the UK.

He was sentenced to 21 months for assisting an offender.

Ali was given a 21-month sentence for withdrawing £300 to give to his friend on 24 January last year, two days before Khawaja left for Syria.

Throughout his almost six months in the Middle East, Khawaja's family never alerted the UK authorities.

Instead they embarked on a relentless campaign of text and social media messaging, desperately pleading with him to return home.

In one exchange, his sister Azmeena berated her brother for deserting the family, saying he had broken his parents' hearts.

In another message, she said: "Book your ticket and come home or I will come and get you."

He told his sister he would not be returning and wanted to "die a martyr".

At the beginning of June last year, Rayat al Tawheed posted an Instagram message stating Khawaja, known by his social media name Abu Daigham al Britaini, had died in battle.

But that post was a deception, Khawaja was already on his way back to the UK in a car driven by his cousin.

The pair were stopped and arrested at the port of Dover on 3 June.

In a letter to the judge read out in court, Khawaja said: "I am sincerely sorry. I have let my country, my family and my community down.

"I have nightmares about Syria. I am lucky to be alive. I would hate to see the young men of Britain make the same mistake I made and say to them 'do not get attracted by the propaganda'."

But prosecutors said they had seen no sign that Khawaja was truly repentant for his crimes. He was, authorities believe, only returning to the UK to raise more funds, before heading back out to Syria and Iraq.