A counter terror expert says lessons have not been learned from terror attacks where perpetrators with radical views have ‘slipped through the cracks’.

Sir Ivor Roberts, from the Counter Extremism Project, and former head of counter-terrorism in the Foreign and Commonwealth Office was speaking on the fifth anniversary of the London Bridge and Borough Market terror attack this weekend.

He referred to the case of Malik Faisal Akram, originally from Blackburn, who carried out an attack on a Texas synagogue in January.

Akram, 44, was shot dead when the FBI entered the place of worship in Colleyville following a 10-hour stand-off.

He held four people hostage during the incident, but they were later released unharmed.

Sir Ivor said: “Despite Akram’s radical views and support of the 9/11 attacks, he had been unsuccessfully referred to Prevent on two separate occasions in 2016 and 2019, MI5 ultimately concluded that he was not a terrorist threat.

“This is a disappointing development from the security services, who do such incredible work on a day-to-day basis to keep us safe.

I encourage MI5 to develop new policies and thorough checks and balances to ensure dangerous individuals don’t slip through the cracks again.”

With regards to the London Bridge and Borough Market terror attack, Sir Ivor said it remains “unclear how much has been learned from this tragedy”.

In a statement on the anniversary, he said: “The 2017 London Bridge attack can be attributed, in significant part, to the failure of the intelligence community to monitor appropriately subjects of interest.

“The primary perpetrator of the attack, Khuram Shazad Butt, was known to both the police and MI5 from as early as 2015.

"At that time he was investigated, but the investigation was quickly ‘moved into the lower echelons’ and his file was classed as ‘low priority’."

London’s mayor has paid tribute to members of the emergency services who “ran towards danger”, as he marked the anniversary.

Sadiq Khan said the capital’s residents will “always stand united in the face of terrorism” as he remembered the victims of the atrocity on June 3, 2017.

Eight people were killed and 48 more injured when terrorists ploughed into pedestrians in a hired van then ran amok with 12in knives.

Christine Archibald, 30, and Xavier Thomas, 45, died after being struck by the van on the bridge.

Alexandre Pigeard, 26, Sara Zelenak, 21, Kirsty Boden, 28, Sebastien Belanger, 36, and James McMullan, 32, were stabbed near the Boro Bistro on the South Bank.

Ignacio Echeverria, 39, died as he tried to protect others from being attacked on nearby Borough High Street.

Ringleader Khuram Butt, 27, Rachid Redouane, 30, and Youssef Zaghba, 22, were confronted in Stoney Street and shot dead by police marksmen.

Meanwhile, a government adviser for social cohesion and resilience, Dame Sara Khan, said engagement with communities about what the counter-terror strategy is must be done “in a much better way”.

The BBC reported Dame Sara as saying the government has failed to explain the strategy to Muslim communities, which “in essence… left a vacuum” about the purpose of the scheme to be “dominated” by Islamists.

She told the BBC’s Political Thinking podcast: “So those types of challenges have continued and I think continuing to engage with communities, explaining what the programme is, addressing concerns – that’s got to continue in a much better way than we’ve seen previously.”