Alex Carlile:

The suicide bomber shows the importance of being able to seize suspects’ passports in certain cases

The death of Jamal al-Harith has brought to an end the terrorist career of a crafty and dangerous man. In his suicide he killed soldiers working to free Mosul from the Islamist tyranny that he supported, and very likely civilians too.

For at least the last 17 years, al-Harith was an active agent of al-Qaeda then Isil. When originally detained in 2001 he was on a terrorist journey to Pakistan. He was taken to Guantanamo Bay. Guantanamo was an American breach of international law and, rightly, al-Harith, a UK citizen, was released in 2004, as a result of UK intervention.

The real questions are about what followed.

Subsequently he and others sued the UK Government on the basis that UK agents were complicit in torture of them in Guantanamo. This allegation of complicity has always been denied, yet he received a large sum in compensation. I hope that what he did with the money was the subject of careful monitoring, something on which we are entitled to some reassurance from the authorities.

The settlement was on the basis that, after testing in the higher courts, there was a requirement that important national security information relevant in some way to his claim, possibly for example as to the credibility of his assertion that he was not a terrorist, would have had to be disclosed to al-Harith, and publicly in court. The Government was not prepared to make such a disclosure, as it would have damaged the public interest disproportionately. This left no option other than to settle his case with a payment. Similar decisions were taken in other cases.

In 2013 the law was changed to enable the secrecy of such documents to be protected. That welcome change should avoid payments in the future to the likes of al-Harith. Nevertheless, the Attorney General should review the position and provide Parliament and the public with the assurance that the public purse will not fund the lives of terrorists in the future.

Al-Harith’s denials of being a terrorist have now been laid bare by the means of his death. Comments that he was radicalised after his time in Guantanamo are contrary to the evidence. Rather, it looks as though he enjoyed a decent lifestyle in Britain for some years after the settlement, and revived his terrorism only when he had lain low long enough for the authorities to have been expected to regard him as less than an immediate threat.

Should the authorities have been more vigilant? I have not seen the evidence of their surveillance after he returned to Britain. But I would expect this to have been extensive, at least until he ceased to be of pressing concern. What we learn from this case is that one should not assume inaction is evidence of lack of ambition.

This raises questions about how we deal with problems posed by similar individuals. Where do we place them in the balance between our valued and vital liberties, and the empirical assessment of necessary security? Vocal and aggressive members of the civil liberties lobby have at times seemed to suggest that it was illegitimate and offensive even to suggest that people who had not been convicted of anything might pose a threat.

We should address this problem again, in a balanced and calm way. It is a truism that some people represent a danger to the public even though it is not possible to convict them of crimes. Purist civil liberties campaigners fail to recognise these realities.

If a person cooperates fully, and in a convincing way, with the Prevent programme, there may be grounds for accepting their rejection of terrorism. Some of our most respected opponents of terrorism once were radicals themselves.

But what to do in the absence of clear evidence of the rejection of terrorism? The al-Harith case illustrates the need further to review the power to deny passports in defined, proportionate circumstances, so that a future al-Harith would be unable to travel. Civil remedies could also be used (and if necessary created) to ensure that suspects be required to report to the police. And watchlists could be kept in operation and effective, so that suspects’ departure could be prevented at UK ports.