More than 150 people reported to the Government's anti-extremism programme went on to attempt or commit serious crimes, including dozens for terrorism offences.

A report published today by the National Audit Office (NAO) found that in the four years to July this year, 156 people referred to the Prevent initiative went on to commit or attempt crimes.

This included 67 people for terrorism-related offences, including the preparation, encouragement, support, financing or commission of terrorism.

It also included membership of banned groups, possession of terrorist materials and collecting information useful for terrorism.

A further 89 people committed or attempted to carry out serious offences such as murder, grievous bodily harm and weapons-related crimes up to seven years after being referred to the flagship programme.

The numbers slipping through the net will raise fresh questions about Prevent's effectiveness following a string of damning high-profile revelations.

Last year it emerged the Prevent scheme 'prematurely' closed its case on Southport attacker Axel Rudakubana three years before he went on to murder three children.

Rudakubana had already discussed the Manchester Arena bombing and stabbing people when Prevent decided to end its involvement with him.

The killer was referred to Prevent three times between 2019 and 2021 due to his interest in terrorist attacks and school shootings, but there was no evidence of a fixed ideology or motivation.

Rudakubana was 17 when he stabbed 11 children and two adults in July 2024, killing nine-year-old Alice da Silva Aguiar, Elsie Dot Stancombe, seven, and six-year-old Bebe King.

In another serious failing, the killer of MP Sir David Amess was removed 'too quickly' from the Prevent programme, a review concluded last year.

Ali Harbi Ali, a supporter of Islamic State, fatally stabbed the serving Conservative MP for Southend West at a constituency surgery event in 2021.

A review found 'questionable decision-making and sub-optimal handling of the case' during the time he was engaged with Prevent.

The NAO report found a record 10,293 referrals were made to Prevent in the 12 months to September 2025 – a 39 per cent surge following the Southport attack.

Less than a third (30 per cent) could be linked to a clear, dominant extremist ideology such as Islamist or Right-wing extremism.

This was down from 73 per cent in the year to September 2017.

Around 8 per cent – roughly 823 referrals – were categorised as having a 'fascination with extreme violence or mass-casualty attacks' without a clear ideology, like in Rudakubana's case.

However, more than three-quarters of the total 10,293 referrals (78 per cent) were dismissed as officials 'assessed the individual as not being at risk of radicalisation'.

The scale of referrals without a specific ideology suggests growing numbers of young people could be having their minds poisoned by online content, particularly social media.

The NAO report criticised the Home Office for financial blunders which meant it underspent its £23.4million Prevent budget by 28 per cent.

It also said the department has failed to properly assess the effectiveness of Channel, a linked service which aims to de-radicalise people if their Prevent referral is upheld.

Gareth Davies, head of the NAO, said: 'The Home Office needs to strengthen its financial management, oversight and evaluation of the programme.'

A Home Office spokesman said: 'Prevent plays a critical role in protecting the public by stopping people from being drawn into terrorism. Since 2015, Prevent has delivered interventions to support over 6,000 people away from violent ideologies, keeping people safe.

'We have made significant changes to strengthen Prevent over recent years. That includes strengthening the response to repeat referrals and making clear that a clear identifiable ideology is not mandatory, so that people at risk do not fall through gaps in the system.'