Convicted terrorists are extremely unlikely to reoffend compared with other prisoners, research by academics and security services in Europe has found.

The research shows that less than 5% of convicted terrorists commit a second terrorist offence after leaving prison. In England and Wales, around 45% of all prisoners will reoffend within a year of release.

The research was conducted in Belgium, which has faced Islamist terrorism since the early 1990s and became one of the centres of the Islamic State campaign in Europe in 2015 and 2016.

The forthcoming release of thousands of extremists imprisoned for terrorist offences has worried security services in the UK and elsewhere.

Britain has recently passed a law ensuring that people convicted of serious terrorist offences will no longer automatically be released halfway through their sentences, following two high-profile attacks by men who had recently left prison.

In November Usman Khan stabbed two people to death near London Bridge, around a year after being released on licence. Khan had been been sentenced in 2012 for his part in an al-Qaida-inspired plot to bomb high-profile locations, and was attending a conference on prisoner rehabilitation when he launched his attack.

In February Sudesh Amman was shot dead by police in Streatham, London, after stabbing two people. The 20-year-old had been freed after serving half his sentence of more than three years for the possession and distribution of extremist material, and was under active police surveillance.

The new research, to be published in the CTC Sentinel, the publication of the Combating Terrorism Center at West Point, the US military academy, suggests such cases are rare.

Less than 3% of the 557 individuals in Belgium included in the study were convicted a second time of a terrorist offence, and less than 5% returned to extremist activities after being released from prison.

Two recent evaluations from the Belgian counter-terrorism services support the new findings. They concluded that 84% of the male returnees from Syria and 95% of women returnees had distanced themselves from extremism.

“These evaluations, together with the literature on terrorist recidivism, tend to suggest that most terrorist convicts simply do not seek to return to their ‘old habits,’ contrary to the dominant perception,” said Thomas Renard, a senior research fellow at the Egmont Institute and the author of the new research.

The two intelligence service evaluations did, however, find that a minority of released offenders remain “of high concern”, suggesting that “a small number of die-hards will remain active across successive waves of jihadi militancy, and remain a key concern for police and intelligence services”.

There are more than 4,000 inmates in western Europe who are either returning foreign fighters, convicted terrorists, radicalised inmates or “vulnerable to radicalisation”. There are about 1,700 in France, of whom 90% will be released within five years, and 700 in the UK.

The new research is supported by other academic studies that consistently indicate a very low rate of terrorist recidivism, compared with the average rates of criminal recidivism, which are generally between 40% and 60% worldwide.

Even before the 2019 London stabbing attacks, the management of released terrorist offenders had been identified as a political priority.

There have been a number of high-profile recidivists, such as Cherif Kouachi, who launched an attack against the staff of the French satirical magazine Charlie Hebdo in January 2015, and Ayman al-Zawahiri, the current leader of al-Qaida.

The fear of recidivism is further reinforced by concerns about prisons, which have been commonly described as “breeding grounds for radicalisation” or “universities of jihad”.

In the UK, an independent review of Islamist extremism in prisons concluded in 2016 that radicalisation in prison was a growing problem that was poorly handled.