Wednesday sees the formal dispatch from the House of Lords of what the wilder critics have named my "Secret Courts Bill". The Bill's passage has so far aroused great passion and debate - as any Bill which seeks to deliver the twin imperatives of justice and security must always do.

The denouement was arrived at last week when peers voted on the shape in which the Bill should leave their House. The three resulting government defeats triggered inevitable headlines pronouncing "chaos" and "humiliation".

But in amongst the traditional enjoyment of significant government defeats something rather important has been missed. By far the biggest defeat of the night was that afforded to a reckless backbench Labour attempt to destroy the Bill entirely.

An extraordinary coalition of world-renowned experts: senior judicial figures, QCs, former intelligence chiefs and former Cabinet Ministers came together to make clear that in their view we are faced with a genuine problem, and that extending the availability of Labour's 'Closed Material Procedures' (CMPs) to national security sensitive civil cases is indeed the solution.

The problem is worth re-iterating. It centres on the highly unsatisfactory rules which currently prevent British judges from taking sensitive national security evidence into account when deciding a case. This makes it impossible for them to untangle the claims and counter-claims about alleged British involvement in the mistreatment of detainees. Indeed it prevents them from scrutinising the secret actions of the state almost entirely.

The further side-effect of this is that because the government is prevented from putting its side of the case to the court, claimants do not have their case heard properly. The taxpayer could then be liable for the millions of pounds potentially required to pay off claims to people who have not proved their case and could be linked to terrorism.

The increasing number of these sorts of cases not only threatens to make the British legal system a hub for this sort of litigation, it has also focussed the attention of our agents and allies on the discretion British judges to look at material and agree that it would damage national security if revealed in open court but, nevertheless, decide it must be disclosed anyway. This is damaging our international reputation as a country that can keep secrets.

The House of Lords has confirmed that the obvious common sense solution to this problem is to change the law and get this material in front of a judge in a closed hearing. They are not ideal; no hearing which the claimant is unable to attend ever is. But they are at least an improvement on the total secrecy of the current system. Some justice - even closed justice - is better than none.

The strange thing is that at one time the human rights lobbies who argue so vociferously against this Bill thought the same. It was their intervention in the case of Chahal in the late 1990s that actually saw the system of closed hearings developed. Now they say that CMPs prevent the government from ever losing and put it above the rule of law.

This is hardly borne out by the evidence. Take Abu Qatada who won in a closed hearing a fortnight ago. Or Ekaterina Zatuliveter, the Russian girlfriend of a Liberal Democrat MP who won her deportation case after a closed hearing. Or Maya Evans who agreed to a closed hearing because it was the only way to get her case resolved. It is quite clear that CMPs are quite simply better where the alternative is silence.

If further proof is needed that the Justice & Security Bill is no '90 days' - or even '42 days' - it is provided by the famously liberal former MI5 chief Eliza Manningham Buller. It was her maiden speech arguing against the extension of the legal pre-charge detention period which sank that policy. By contrast she has argued compellingly for the introduction of closed hearings to "give the opportunity for... material, which may or may not reflect badly on the security and intelligence services to be looked at."

If we do not get the Bill right we will perpetuate these serious gaps both in our legal system and in our national security. We will also risk money disappearing hand over fist into the pockets of our enemies. It is through this prism that I will be examining some of the arguments that have been made for change by the House of Lords: reasoned argument I am prepared to listen to, legal purism which takes leave of reality I am not.