A stabbing attack by a convicted terrorist that wounded two people on Streatham High Road could have been prevented, an inquest jury has concluded.

The 20-year-old jihadist Sudesh Amman was shot dead by two of nine covert officers who were tracking him on 2 February 2020 after he wounded a man and woman on the street while wearing a fake suicide belt, the inquest heard.

After a two-and-a-half-week hearing at the Royal Courts of Justice, jurors concluded on Friday that Amman was lawfully killed, having been directed to do so by the coroner, Mr Justice Hilliard.

But they also found that an opportunity was missed by police and probation services to intervene earlier to prevent the attack. The attack may have been prevented had Amman been recalled to prison after buying items used in his fake suicide belt, jurors concluded.

Just over a week before the attack, Amman had been released from Belmarsh high security prison into the community to serve the remainder of his 40-month sentence for terrorist offences on licence. Amman was released despite concerns from the police and MI5 that he was “one of the most dangerous individuals” in the country, with an “extremist mindset” and likely to attack.

Two days before the attack, Amman was seen purchasing items including four small bottles of Irn-Bru, parcel tape and tinfoil, leading to correct suspicions that he was planning to make a hoax suicide belt.

The police increased their security against Amman to an armed round-the-clock operation but they decided against searching his probation hostel flat for fear of alerting him to the surveillance.

The inquest jury concluded the police were right not to search his flat, but found that Amman should have been recalled to prison following the purchases for the hoax device.

The jury also concluded that the police were right not to stop and search Amman when he left his probation hostel 30 minutes before the attack. Hilliard praised the bravery of the police on the day.

At the inquest’s conclusion, he said: “The Metropolitan police surveillance teams were prepared to put themselves in harm’s way. They are all to be commended for their bravery, and they are owed a considerable debt of gratitude for their bravery.”

The inquest heard that Amman was shot at six times after lunging at officers during a stabbing attack that last 62 seconds from the moment he stole a knife from a hardware store. Between two and four bullets hit Amman and he was declared dead 90 minutes later after a ballistics officer concluded the fake suicide belt he was wearing was safe, the inquest heard.

Amman was born in December 1999 in Coventry and was the oldest of six boys of Sri Lankan descent. He was convicted in 2018 of 13 counts of collecting material useful for terrorism and disseminating terrorist publications.