Isis has claimed responsibility for the Streatham terror attack.

The group issued a generically-worded statement on its official propaganda channels on Monday morning saying the stabbing was carried out by an Isis “soldier”.

It said he was responding to calls for attacks on citizens of countries bombing Isis territories, which have since been lost in Syria and Iraq.

Isis’s statement contained no new details of the attack or the perpetrator, meaning it may have been based on media reports rather than direct communication with Sudesh Amman.

The terrorist organisation has claimed numerous attacks without proof, including the Fishmongers’ Hall stabbing in November.

Streatham attack: Man shot dead by police after stabbings Show all 22 1 /22 Streatham attack: Man shot dead by police after stabbings Streatham attack: Man shot dead by police after stabbings Armed police officers on Streatham High Road. The Metropolitan Police warned people to stay away from the Streatham area boguta37/PA Streatham attack: Man shot dead by police after stabbings The man was shot dead by police after two stabbed in 'Islamist-related' terror attack in London boguta37/PA Streatham attack: Man shot dead by police after stabbings Sudesh Amman, the attacker, has been named as a convicted terror offender who was released from prison days ago Metropolitan Police/PA Streatham attack: Man shot dead by police after stabbings Items left on the pavement at the scene in Streatham High Road Isis supporter Amman was just 18 when he was jailed in December 2018 after police found a stash of bomb-making manuals and other propaganda. Now 20, he had declared his own wish to carry out a terror attack and stockpiled a combat knife, air gun and black flag at his family home in London PA Streatham attack: Man shot dead by police after stabbings He was being monitored by undercover police and being followed as part of a “proactive counterterrorism operation” when he started the rampage in Streatham AP Streatham attack: Man shot dead by police after stabbings Amman was able to stab two people before being shot dead by armed officers outside a busy row of shops Gabriel Video/PA Streatham attack: Man shot dead by police after stabbings A woman reacts as police officers interview people near to the scene Getty Streatham attack: Man shot dead by police after stabbings An armed police officer on Streatham High Road Deputy Assistant Commissioner Lucy D’Orsi said Amman was wearing a fake suicide ves Gully/PA Streatham attack: Man shot dead by police after stabbings Police forensic officers work outside of a Boots store AFP via Getty Streatham attack: Man shot dead by police after stabbings Police officers at the scene Getty Streatham attack: Man shot dead by police after stabbings A police forensic officer works at the scene in Streatham High Road PA Streatham attack: Man shot dead by police after stabbings Items left on the pavement at the scene in Streatham High Road PA Streatham attack: Man shot dead by police after stabbings A police officer on the scene Dave Chawner/SWNS Streatham attack: Man shot dead by police after stabbings Police forensic officers are seen near the site Reuters Streatham attack: Man shot dead by police after stabbings Police officers on the scene outside an Iceland supermarket Andy Bullemor/SWNS Streatham attack: Man shot dead by police after stabbings Police are seen near a site where a man was shot Reuters Streatham attack: Man shot dead by police after stabbings A policeman secures the site of the incident EPA Streatham attack: Man shot dead by police after stabbings A view of the scene Megan Tobeck Streatham attack: Man shot dead by police after stabbings Armed police at the scene in Streatham High Road PA Streatham attack: Man shot dead by police after stabbings A view of the scene Michael Owens Streatham attack: Man shot dead by police after stabbings Police forensic officers at the scene PA Streatham attack: Man shot dead by police after stabbings A Police officer is seen near a site where a man was shot Reuters

Amman had been jailed for collecting and distributing terrorist material, and his trial heard that he had declared a pledge of allegiance to Isis.

Prosecutors said he had a “fascination with dying in the name of terrorism”, discussed carrying a knife attack and listed becoming a martyr as his top life goal.

He posted a photo of a knife and two guns on top of a black Islamist flag, with the caption “armed and ready 3 April” before his arrest, but was not charged with preparing an act of terrorism.

Amman was handed a three year and four month sentence in December 2018 for disseminating terrorist material and collecting information useful for terror attacks.

He was released last week after serving half of his jail sentence, after a total of 20 months in custody since his original arrest.

Amman's, mother Haleema Faraz Khan, told Sky News that he was a “nice, polite boy” who had seemed “normal” when she visited him at his probation hostel on Thursday.

She said he had become more religious since being in prison, and that she believed he had been radicalised while in HMP Belmarsh.

“He became more religious inside prison, that's where I think he became radicalised,” she added.

“He was watching and listening to things online which brainwashed him.”

Concerns have frequently been raised about terrorist networking inside the prison.

Sadiq Khan warns Streatham attack was 'preventable'

Ms Khan also said that Amman, the eldest of her five sons, had also developed extreme views after looking at Islamist material online.

His 2018 trial heard that he had started collecting terrorist material online at the age of 17 and was active on Telegram - then Isis's main platform.

The Metropolitan Police said he was being followed by undercover officers as part of a “proactive operation” when he launched his knife attack in a busy shopping street on Sunday afternoon.

He stabbed two people, who survived, before being shot dead by police.

Like other recent Isis-inspired attackers, Amman was wearing a fake suicide vest that ensured police would shoot to kill.

It was the third terror attack in just over two months to be carried out by a convicted terrorist in Britain, following stabbings at Fishmongers’ Hall and inside HMP Whitemoor.

The former head of counterterror police warned that “more dangerous people” are now being released from British prisons than returning from Syria.

There are currently more than 200 people jailed for terror offences in the UK, but up to 800 flagged as potential extremists and prison officers fear the real number is far higher.

Recent cases have shown that terrorists are able to network and radicalise others inside prisons, and may be faking apparent compliance with deradicalisation schemes.

The government recently announced a package of new terror measures including lie detector tests for released terrorists and changes to make them serve longer in jail.

Further proposals were to be announced on Monday but there are mounting concerns that imprisoning extremists could actually be increasing the risk they pose because of a lack of control and effective deradicalisation work.

British security services have foiled 24 attack plots – 16 Islamist and eight far-right – since March 2017.

But the head of counterterror police has admitted that softer targets and more simple plots have become harder to stop.

In 2014 a speech by Isis's spokesperson called for indiscriminate attacks on all non-Muslims, particularly in countries including Britain in the US-led coalition bombing its territories.