Streatham attack: Met Police chief defends officers who failed to prevent stabbing despite following Sudesh Amman

Dame Cressida Dick calls attack 'totally unexpected' as head of UK counterterror police admits they cannot watch all potential terrorists

Britain’s most senior police officer has defended the undercover police officers who were following a terrorist when he launched an attack in Streatham on Sunday afternoon.

Sudesh Amman was able to stab two people before being shot dead by plain-clothed armed police.

Dame Cressida Dick, commissioner of the Metropolitan Police, was questioned over whether the attack could have been prevented by the London Assembly on Wednesday.

“They are conducting covert surveillance, so they are not of course providing man-to-man marking,” she said.

“They are there covertly and that is a deliberate thing. It is inevitable that there could be a time delay before somebody totally unexpectedly does something.”

Amman had grabbed the knife from inside a shop, but was already wearing a fake suicide vest in apparent preparation for an attack.

Scotland Yard previously said the device “had been concealed under his clothes”, suggesting the officers did not see it until after he started stabbing people.

Dame Cressida added: “I wish I could assure the public that everybody who poses a risk on the streets could be subject to some sort of thing that would stop them being able to stab anybody ever, but it is clearly not possible.”

She spoke as assistant commissioner Neil Basu, the head of UK counterterror police, called for people to report any suspicious behaviour and help stop radicalisation.

“The threat is, despite our best efforts, not diminishing,” he wrote in the Evening Standard.

“With 3,000 or so subjects of interest currently on our radar and many convicted terrorists soon due to be released from prison, we simply cannot watch all of them, all the time.”

Undercover officers had been following Amman on foot through Streatham, where he had been placed in a probation hostel, for 40 minutes when he entered a shop on the High Road.

He stole a knife and ran out while being chased by a member of staff, then removed the packaging and stabbed two passers-by, who survived.

Scotland Yard said Amman was inside the shop for less than a minute, and that he was shot dead within 60 seconds of starting the attack.

It came little after a week after he was automatically released from prison, half-way through a sentence for collecting and distributing material useful for terror attacks.

Amman had originally been arrested on suspicion of planning an attack in May 2018, after writing that he was “armed and ready” online, declaring support for Isis and encouraging his girlfriend to behead her non-Muslim parents.

But he was charged with lesser offences on advice from the Crown Prosecution Service and received a sentence of three years and four months.

The Independent Office for Police Conduct is investigating the shooting of Amman, as is standard when any police operation ends in a death.

Dame Cressida would not comment on whether he was subject to a Terrorism Prevention and Investigation Measure (TPIM), which place enhanced restrictions on extremists who cannot be prosecuted because of national security issues, or deported.

Only five people in Britain are subject to a TPIM, according to official figures up to the end of November.

The Streatham stabbing was the third terror attack in little over two months to be committed by a convicted terror offender, following the incidents at Fishmongers’ Hall and inside HMP Whitemoor.

It sparked a vow by the government to bring in emergency laws that would stop the automatic release of terror offenders currently in prison and ensure they are assessed by the Parole Board.

But ministers have been warned that “unintended consequences” of the hastily drawn-up plans, which could mean the board refuses to release terrorists on licence until their sentence expires.

That would see extremists released from jail without conditions that currently restrict their movement, communications and association until the end of their sentence.

Asked about the proposals, Dame Cressida said: “If there are to be changes to the sentencing regime, the one thing we would be asking for is that people should still be released as they are under the current regime under strong conditions, licence conditions.”

Downing Street said there would also be a full review of the maximum prison sentences for terror offences, including looking at whether offenders of all levels of seriousness should be held in jail indefinitely until the Parole Board assesses they are no longer a threat to the public.

The plans have raised concerns over radicalisation inside British prisons, where recent cases have shown that terrorists are able to network and spread extremism.

Amman’s mother claimed he had been further radicalised inside HMP Belmarsh, where a former inmate told The Times he openly stated his wish to carry out a terror attack and conducted a mock Isis execution.

There are already up to 800 flagged extremists in British jails - almost four times the number of terrorist prisoners - and there have been repeated official warnings about Islamist radicalisation including from the Parole Board and a government review.

Figures suggest that around 50 terror offenders could be released from British prisons this year, with 224 inside as of the most recent count.

Additional reporting by PA