Leading Article: Details, please, Sir Nicholas

AS Attorney General, Sir Nicholas Lyell will appreciate better than most the inexorable process by which almost all legal cases proceed to a dramatic climax, be it the cross-examination that decides a trial or the moment when a verdict is given. It is therefore with some trepidation that he must approach today's hearing of the Scott inquiry. For here is a case in which almost all the questions raised during the long voyage of discovery through the arms-to-Iraq affair come back to the Attorney General himself.

The fundamental question is how the established system of Public Interest Immunity certificates came to be perverted. They were used to avoid embarrassment for a faction within the apparatus of state that had charge of our policy towards a dangerous and important foreign power. Theirs was diplomacy of the bleakest moral nature, subjected to no parliamentary debate and rarely, if ever, tested in cabinet discussion. It is no surprise that Sir Nicholas was not privy to the secret papers involved. But his apparent exclusion from the full evidence, combined with his readiness to press immunity certificates upon ministers, almost sent innocent men to jail.

No doubt Lord Justice Scott will pronounce later this year upon the broad issue of how any government may use such certificates, the modern equivalent of crown privilege. But in the meantime Sir Nicholas will be called upon to answer in forensic detail the many questions that flowed from this unhappy prosecution. When, for example, did he become aware of the involvement of the secret intelligence service, which was using the defendants as its agents? How much was he told, and how early in the proceedings? Was it not mere political convenience that persuaded ministers to sign the certificates withholding crucial evidence?

Sir Nicholas will doubtless say that he consulted eminent opinion before placing the certificates before ministers. Well and good, but were these worthies aware of the facts or were they rendering an opinion upon abstract law? Lord Justice Scott may also wish to hear the truth about Michael Heseltine's self-proclaimed reluctance to sign one certificate and why his reservations were not taken into account.

Most of all, the inquiry needs to hear why Sir Nicholas, in possession of many of the facts if not the whole picture, allowed Her Majesty's Customs and Excise to undertake a flawed prosecution - and, by the way, to stand piously on the principle of that department's legal independence will not wash. Sir Nicholas could have put a stop to the case. In the climate of the times, of course, he was hardly likely to.

Now he has been called to account. It is perfectly in order to say that nobody need take the consequences of their actions until Lord Justice Scott has delivered his findings. But if the Attorney General does not acquit himself with honour and clarity today, it is doubtful whether he can continue to perform his duties to full effect.