The terrorist bomb detonated at a Liverpool hospital may have gone off when it was "jostled" as the taxi in which the bomber was travelling came to a stop, with investigators admitting: "We got lucky."

       A search of Emad al-Swealmeen's home and an examination of his online purchases showed he was attempting to build a sophisticated, powerful bomb that would have caused "damage, death and destruction" on a huge scale.

       The Telegraph can also reveal that the 32-year-old, who converted to Christianity, was seen at his local mosque every day during Ramadan in April, around the same time time he began constructing his bomb.

       Sources claim the Iraqi-born asylum seeker attended the mosque "all day every day" during the religious festival and was seen praying with a fellow Muslim a week before the attack.

       The revelation will further fuel suspicion that Swealmeen's conversion to Christianity four years ago was a ploy to help him persuade the Home Office to let him stay in the UK.

       Counter-terrorism police and intelligence agencies remain unclear as to Swealmeen's intended target – either the Liverpool Women's Hospital where the explosion occurred or the Remembrance Sunday service at Liverpool Cathedral, under a mile away.

       They increasingly believe it was an Islamist attack although they cannot rule out that the state of the terrorist's mental health may also have played a part.

       A source said: "Methodology wise, this attack is entirely jihadist – but we have an open mind as to what precisely was motivating him. If he built a much more destructive device then the detonation looks accidental. It looks lucky."

       While investigators continue building a picture of what happened on Sunday, sources have said it is possible the sensitive detonator went off accidentally, killing Swealmeen.

       "In moving to get ready to get out of the taxi, he might have set it off. Or else, as the vehicle has come to a stop, he has dropped it or jostled it and it has gone off," said a source. Home-made devices are inherently unstable.

       Police have uncovered at least two types of explosives in Swealmeen's flat, and chemicals purchased online suggest he had built a sophisticated detonator intended to set off a much larger bomb.

       On Wednesday, residents living close to the property in Sutcliffe Street, in the Kensington area of Liverpool, were evacuated when police found "several suspicious packages".

       Evidence uncovered so far suggests Swealmeen's device was smaller than the bomb constructed by Salman Abedi, the Manchester Arena suicide bomber who murdered 22 people and wounded hundreds more.

       One likelihood is that the bomb was being constructed using the HMTD high explosive, similar to that used in the 7/7 attacks in London in 2005.

       A source said it appeared Swealmeen had built a primer and a secondary explosive, using two different chemical explosives purchased on the internet.

       Intelligence agencies are scouring for any associates who might also be involved but currently believe he was acting alone and in all likelihood found plans to construct the bomb online.

       On Wednesday, police confirmed that a post-mortem examination showed Swealmeen had died as a result of injuries sustained from fire and explosion.

       Assistant Chief Constable Russ Jackson, the head of counter-terrorism policing North West, said: "A complex picture is emerging over the purchases of the component parts of the device. We know that Swealmeen rented the property from April this year and we believe relevant purchases have been made at least since that time.

       "We have now traced a next of kin for Swealmeen who has informed us that he was born in Iraq. Our enquiries have found that Swealmeen has had episodes of mental illness. This will form part of the investigation and will take some time to fully understand."

       Meanwhile, more details of Swealmeen's asylum status have emerged, revealing that, despite being turned down in 2015, his case was still unresolved when he blew himself up at the weekend.

       After first arriving in the UK from Dubai, he lodged an application for leave to remain, claiming to be a Syrian refugee whose life would be in danger if he returned home.

       The hearing took place on April 16, 2015, but after testing the veracity of his claims, Home Office officials rejected the application on June 2 that year because they did not believe he was Syrian. Swealmeen sought leave to appeal the decision, but that was refused in August 2015.

       On March 27, 2017, he was confirmed into the Church of England at Liverpool Cathedral and also changed his name to Enzo Almeni in tribute to his motor-racing hero, Enzo Ferrari.

       In January this year, he lodged a fresh application with the Home Office, using his new name and arguing that his Christian faith would lead to his persecution if returned to the Middle East. That application was still being processed at the weekend when he blew himself up outside Liverpool Women's Hospital.

       It is thought some of the delays might be down to the backlog caused by the pandemic, but on Wednesday Priti Patel, the Home Secretary, said the case illustrated the "merry-go-round'' of a broken asylum system.

       It comes as Assistant Commissioner Matt Jukes, the head of counter-terror policing, warned that the public needed to be vigilant in the run-up to Christmas amid concern about more attacks.

       He said: "Just as we enter the first busy festive period since the start of the pandemic, the terror threat level has been raised to severe, meaning an attack is highly likely. I know that will concern people, but policing is stepping up our activity to protect the UK. It also means that we need the public to do the same, by being more vigilant and trusting us with their concerns."