A former public schoolboy who converted to an extremist strand of Islam, manufactured explosives and made a suicide bomb vest was jailed yesterday for plotting “carnage” at a crowded shopping centre.

Andrew Ibrahim, who changed his name to Isa in 2007 after his religious conversion, was arrested after members of the Muslim community in Bristol became concerned about his behaviour and contacted police.

Ibrahim, the son of an NHS pathologist, was convicted of making an explosive with intent to endanger life and preparing terrorist acts.

Mr Justice Butterfield imposed an indeterminate sentence at Winchester Crown Court and told Ibrahim, now 20, that he should serve at least ten years. His mother, Valerie, a university administrator, left the court in tears.

Ibrahim’s conviction, after a month-long trial, is the first visible success for the Prevent element of the national counter-terrorism strategy that enlists the help of British Muslims in the fight against radicalisation. The alert was raised when a representative from a city mosque interrupted a Special Branch officer’s canal boat holiday with a concerned phone call.

Detective Chief Inspector Kevin Hazell, of Avon and Somerset police, said: “They didn’t like his view of Islam, particularly his praise for suicide bombers, and were especially alarmed when he had a heated row with a visiting imam. The calls to us came in when he showed some people the injuries on his hands, including marks from shards of glass, which he said were caused when a bottle blew up when he was mixing chemicals.”

Detectives found Ibrahim — who was estranged from his family after becoming a heroin addict — at the GP’s surgery where he collected his methadone prescription. They then discovered the flat in Comb Paddock, a cul-de-sac in the suburb of Westbury-on-Trym, where he had been manufacturing explosives, wiring detonators and stitching a suicide vest.

A search in April last year revealed the high explosive hexamethylene triperoxide diamine (HMTD) in a biscuit tin in the fridge, a crude detonator circuit under the kitchen sink and the vest, with pockets to carry explosives, hanging on the bedroom door.

CCTV footage from the Broadmead shopping centre showed him on a reconnaissance trip during which he made notes on his mobile phone. One read: “Food Court dense area”.

Ibrahim was born Andrew Michael Philip, the younger of two sons of an Egyptian father, Nassif Ibrahim, and an English mother who later separated. Both attended his trial. Nassif Ibrahim, a Coptic Christian, is a consultant at Frenchay Hospital. The court was told that he was a collector of pottery, stamps, coins and Nazi memorabilia.

The would-be bomber was educated for a time as a boarder at Downside School, near Bath. His elder brother Peter is an Oxford graduate who is studying to become a barrister.

Ibrahim drifted into drug use at the age of 12 and by his late teens was a heavy user of heroin and crack. He told the jury that his mother had asked him to leave the family home.

David Spens, QC, for the defence, asked the jury to consider whether his client was “an Islamic extremist intent on carnage and mass murder” or “a prat” who lived in a fantasy world.

The jury’s verdict was that Ibrahim was a would-be terrorist.

Passing sentence, Mr Justice Butterfield told Ibrahim that his preparations for a bomb attack were at an advance stage at the time of his arrest. The judge took account of his age, and that he had acted alone.

Detective Superintendent Nigel Rock said that without help from the Muslim communities Ibrahim might not have been caught. Mr Rock said: “Ibrahim had all the components for a credible explosive device and he had increased its destructive power the night before his arrest by obtaining shrapnel to add to it.”

Ibrahim bought the components for his devices from high street shops, several purchases of hydrogen peroxide from Boots. The chain said it had been reissued with guidance about the sale of hazardous materials. A Home Office spokesman said it advised shops selling some materials “to be more enquiring of new customers and to report suspicious enquiries to police”.

The Council of Bristol Mosques said in a statement: “We condemn, in the strongest terms, any act of terrorism and extremism. Islam has no connection whatsoever with such criminal actions or indeed intentions.”

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