A teenage terror-plotter has been sentenced to eight years for grooming a young man with learning difficulties to carry out a Lee Rigby copycat killing.

Kazi Islam, 19, tried to persuade 19-year-old Harry Thomas to buy the ingredients for a pipe bomb and to attack one or more soldiers with a kitchen knife or meat cleaver on his command.

He encouraged the older youth to start calling himself Haroon instead of Harry and attempted to radicalise him with stories of innocent children murdered by military forces.

But Islam's schemes were foiled when Mr Thomas failed to buy any of the right ingredients for a bomb and let slip to "a few friends" what they were up to.

The defendant, who will serve his sentence in a young offenders institute, denied wrongdoing, saying that he only talked to Mr Thomas about getting the components for a bomb as an "experiment" in radicalisation.

But following the trial at the Old Bailey, Islam, of Meanley Road, Newham, was found guilty of engaging in the preparation of terrorist acts.

Sentencing, judge Richard Marks QC told him that his behaviour towards Mr Thomas, who suffered from Aspergers syndrome and ADHD, was an aggravating feature.

He said: "Even on your own account, that you knew he was an extremely vulnerable young man, your treatment of him was as callous as it was manipulative."

Judge Marks said that since his conviction Islam had shown neither remorse nor insight into the seriousness of what he had done.

He ordered Islam to pay a victim surcharged of £120 and be subject to a terrorism prevention requirement for 15 years.

His lawyer Peter Lownds earlier described his client as something of a "bedroom jihadist" whose plans had never got to the stage of specific discussion or a dry run.

In personal mitigation, he said: "He comes from a very loving and supportive family who are very worried and confused by these events."

The trial heard a series of exchanges on BlackBerry Messenger and social media sites, which were uncovered when police raided the house in east London where Islam lived with his family.

In November 2013, Islam messaged Mr Thomas: "Did u get the ingredients mate?"

Mr Thomas replied that he got "some pipes" but during the course of the conversation it appeared that he got the wrong ones.

In December 2013, Mr Thomas asked: "who're we gonna blow up" and Islam replied "no-one" adding "I'll tell you wen I see you (sic)".

Later that month, Islam tried to disguise the plot with code words when he told Mr Thomas: "So we need to work on this cake."

But Mr Thomas, failing to grasp the subtlety, responded: "cake? U mean the b o m b."

Islam ordered Mr Thomas not to talk to anyone after the older youth admitted he had "only told a few mates", the court heard.

The defendant told him: "Don't tell anyone ... just keep your mouth shut ... The brothers are gonna come after me and kill me and they're gonna kill u as well."

At the time he was arrested, Islam, who failed to pass any GCSEs, was living with his parents and working for Winning Moves based in Paddington, which sells a range of popular family board games including Top Trumps, Monopoly, Cluedo, Risk, Connect 4 and Pass The Pigs.

The practising Muslim said he first became interested in issues surrounding Afghanistan and Iraq because he wanted to find out why Fusilier Rigby had been attacked outside his Woolwich barracks in May 2013.

For "research purposes" he attended meetings and talks held by the banned extremist group al Muhajiroun, viewed Jihadist propaganda online and even downloaded a document entitled How To Make Semtex, he said.

He said he met Mr Thomas on an IT course at Barking and Dagenham College and decided to befriend him in October 2013.

His experiment with Mr Thomas was inspired by Nicky Reilly - another Asperger's syndrome sufferer like Mr Thomas - who had been involved in a failed suicide bombing in Exeter, Islam said.

After he was arrested, police searched Mr Thomas's home but found nothing to suggest he had in fact bought any of the items on his friend's terror shopping list.