Key questions about London Bridge terrorist Usman Khan answered

Was Usman Khan still serving a prison sentence?

Khan was convicted in 2012 of being part of a group of al-Qaida-inspired plotters who intended to carry out attacks in the UK – including on the London Stock Exchange – and set up a terrorist camp in Pakistan.

Khan was released from prison on licence last year and at the time of the attack he was wearing an electronic tag and subject to low-level monitoring. While he was known to the security services, he was considered a low- to medium-priority threat.

What sort of sentence was it?

Khan was jailed after receiving a controversial sentence of imprisonment for public protection (IPP) in 2012. This allowed him to be held in prison indefinitely, with no minimum term, until a parole board agreed he was no longer a threat to the public.

IPPs were introduced under Labour, but abolished by the Conservative-Liberal Democrat coalition government in December 2012 (although, importantly, not retrospectively), amid complaints they had been misused to keep some individuals incarcerated without a proper timetable to be considered for release. IPPs were replaced by extended sentences, which carry a minimum term or tariff to ensure that cases would be reviewed.

Against that backdrop, Khan and two others successfully appealed against their IPP sentences. In 2013, the court of appeal revised Khan’s sentence to a term of 16 years, and told him he would have to spend a minimum of eight years behind bars.

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Who decided to let him out after eight years?

This is where it appears something went wrong. At the time, Lord Justice Leveson at the court of appeal indicated that he expected the Parole Board to review Khan’s case at the end of the eight-year minimum term, describing anybody who had committed such terrorism offences as dangerous.

“There is an argument for concluding that anyone convicted of such an offence should be incentivised to demonstrate that he can safely be released; such a decision is then better left to the Parole Board for consideration proximate in time to the date when release becomes possible,” Leveson said.

But on Saturday morning, the Parole Board put out a statement saying it had not reviewed Khan’s case at all – and that the London Bridge terrorist had been released without its involvement – suggesting the law had been misunderstood or misapplied.

It said: “The Parole Board can confirm it had no involvement with the release of the individual identified as the attacker, who appears to have been released automatically on licence (as required by law), without ever being referred to the Board.”

Are there more cases like this?

An analysis conducted by the Guardian a little over a year ago showed that a growing number of people previously convicted for terror offences are eligible for release. These are typically sentences handed down to people found guilty of attack planning or funding terrorism – rather than those found guilty of violent acts.

The figures showed that more than 80 of the 193 terms issued for these types terror offences between 2007 and 2016 ran out by the end of 2018. The figures exclude those with life or indeterminate sentences, but as in Khan’s case, many will have shown a strong intention to attack at the time.

Such individuals will rarely be placed under active scrutiny by intelligence agencies, leaving them largely in the day-to-day monitoring of the probation service.