In fact, judges could have kept Khan in prison until a parole board felt he was safe to release — under a tough sentencing regime brought in by Labour when David Blunkett was home secretary — but decided to impose a fixed term on him instead.



Khan was sentenced in February 2012, after pleading guilty to engaging in conduct in preparation for acts of terrorism, for his part in a plot which involved building a terrorist training camp in Kashmir.



He was sentenced to an indeterminate sentence for public protection, which meant he would not be released until he was deemed no longer dangerous — a measure that was brought in by the previous Labour government in the Criminal Justice Act 2003, and scrapped by the coalition. Although the sentences are no longer handed out by the courts, they were not abolished for prisoners still serving IPPs.

However, Khan's sentence was reviewed by the Court of Appeal in 2013, which decided that he should serve a 16-year-fixed term, with half of that time spent in prison, plus an extended five years on license. The court could have decided to uphold the IPP sentence if it wished.

A Conservative source said that Johnson's framing of the situation was intended to demonstrate that the court was applying the law as made by Parliament. Because Khan was deemed dangerous, the "only option" — in terms of a decision to be made by the Court of Appeal, was to issue him with a sentence that had an automatic release.



The court decided that the lower court should not have distinguished between the groups of men sentenced at the same time — Khan's from Stoke-on-Trent, and another from Cardiff and London who had plotted to blow up the London Stock Exchange. The second group received extended sentences, and the court decided that both should have been regarded as "equally serious."

"The risk posed to the public could not be greater from those who were very much further away from realising their apparent goal than those who were far closer to doing so," their judgment said.

Marr pointed out that the Conservatives have been in power for almost a decade, and, as the party of government, had the ability to change a sentencing framework if they believed to be too lenient.

Marr said: "Under the Conservative he was let out... this was a Conservative decision... for ten years you've done nothing about it."