Salman Abedi once called RE teacher an 'Islamophobe' for asking his opinion of suicide bombers

Manchester attacker also called Brits 'infidels' who were 'unjust to Arabs'

Salman Abedi once accused a teacher of Islamophobia after being challenged on what he thought of suicide bombings, it has emerged.

As a teenager at the Burnage Academy for Boys, he was among an Arabic-speaking group of friends who launched a complaint after the teacher “asked what they thought of someone who would strap on a bomb and blow people up”, The Times reported.

“A group went to complain to their RE teacher saying it was Islamophobic,” a source said.

Former acquaintances of the Manchester attacker have remembered him as a cannabis-smoking, drinking, sometimes angry teenager who underwent an abrupt transformation within recent years.

After his family moved back to Libya during the overthrow of Muammar Gaddafi, he made frequent visits to the war-torn country but stayed living in Manchester with his brother.

As signs of Abedi’s radicalisation grew, seeing him appear increasingly pious while flying a black Islamist flag from his home, the alarm was repeatedly raised.

Around five years ago, two people who know the 22-year-old at college called the police anti-terror hotline after he told them “being a suicide bomber was okay”.

Two community leaders also reported Abedi over his extremist views in 2015, fearing he was already involved in terror networks.

He was banned from Didsbury Mosque and reported again to authorities after criticising an imam who delivered a sermon condemning Isis.

One of Abedi’s said he had felt increasing frustration at his treatment in the UK, which was heightened after a friend was stabbed to death in what he perceived to be a religious hate crime.

She added that the British-born bomber began referring to others in the country as “infidels” who were “unjust to Arabs”.

Abedi’s family had reportedly warned authorities he was “dangerous”, moving him and his younger brother to Libya in April to keep a closer eye, months after Abedi dropped out of his business degree at Salford University.

But he returned to Manchester, flying via Istanbul and Düsseldorf on 18 May but apparently failing to flag up on any international databases or warning systems.

Four days later, he detonated a suicide bomb in the foyer of Manchester Arena as thousands of young Ariana Grande fans streamed out of a concert, killing seven people.

Libyan authorities, who are questioning Abedi's parents and siblings in Tripoli, claimed he made a final phone call to his brother and mother before the attack, in which he said: “Forgive me.”

The Home Secretary, Amber Rudd, has admitted Abedi was “known up to a point” to security services but they will be examining how so many opportunities to stop the terrorist were missed.

He is believed to be part of a far wider network including prolific Isis recruiter Raphael Hostey, also from Manchester, who was killed in a drone strike in Syria last year.

Counter-terror police made a fresh arrest in Moss Side in the early hours of Friday morning, while searches were being carried out at a separate arrest.

Eight men are currently being questioned in relation to the attack, with a man and woman who were previously arrested released without charge.

With the UK on critical alert, meaning another attack is expected imminently, thousands of soldiers have been deployed at sensitive sites to support overstretched police.

British police have resumed “working closely” with US authorities on the probe after a row over intelligence leaked to American media outlets.