A Muslim convert and associate of hate preacher Anjem Choudary is facing a substantial jail term after knocking a teenage boy unconscious for cuddling his own girlfriend.

Michael Coe, 35, was driving through east London when he spotted the two 16-year-olds hugging on the pavement. He pulled over to confront the pair, demanding to know if they were Muslims and calling the girl a “whore”.

He then grabbed the boy by the throat and threw him to the ground, kicking his head and leaving him unconscious and bleeding from two injuries. When passing schoolteacher Boutho Siwela tried to come to the teenager’s aid, he was also attacked.

Coe admitted “shoving” the boy, but claimed he was acting in self-defence. He was convicted after a trial at Southwark crown court of assault occasioning actual bodily harm and battery in Wilson Road, Newham, on 15 April.

The jury returned unanimous guilty verdicts after 90 minutes of deliberation.

Coe was convicted of a similar offence in May 2013, after getting out of his car to confront a group of young people about their “inappropriate language” on an estate in east London. During that incident, he allegedly called a girl a “slut” and the others “kafir scum”.

Judge Michael Gledhill described Coe as a danger to the public and warned him that he faced a “substantial” term of imprisonment. Sentencing was adjourned until 21 September for further reports.

Coe has a long record of offences starting when he was 16, including assaults, burglary, robbery and violent disorder. He was radicalised in prison by terrorist plotter Dhiren Barot in 2007, while serving an eight-year term for firing a shotgun at police during an arrest.

Since known as Mikaeel Ibrahim, Coe later became a close associate of Choudary, who was convicted last week of supporting Islamic State. He was also on a list of individuals that Choudary was banned from having contact with while the hate preacher was on bail.

Coe was photographed at a demonstration on the 10th anniversary of the September 11 attacks. In December 2013, he took part in a protest in Brick Lane, east London, against Muslim shopkeepers selling alcohol.

The married father of two was jailed for 15 months after being found in the back of a lorry with false ID documents at the Kent port of Dover in November 2014. He was accused of planning to travel to Syria to join Isis, but was acquitted of engaging in conduct in preparation for terrorist acts.