Leading Article: If it wasn't MI5, who was it?

KENNETH CLARKE made an error of judgement yesterday in instantly dismissing a claim in the Sun that the secret services had taped the conversation between the Prince and Princess of Wales which both it and the Daily Mirror printed. Without having had time to check it out, the Home Secretary described the claim as 'silly' and 'nonsense'. In terms even more insulting to the public's intelligence, he likened it to a hoary old tabloid newspaper story about the B-52 bomber found on the moon. Later in the day he was supported by sources in Downing Street, who ruled out any possibility of MI5 involvement.

Mr Clarke has done this before. In January he described as 'wild and extremely silly' allegations that MI5 or GCHQ, the Government's listening station at Cheltenham, had been involved in recording the so-called Camilla-gate conversation attributed to Prince Charles and his friend Camilla Parker- Bowles. In a similar spirit, the Government claimed a fortnight ago that two reports by senior judges had exonerated the secret services from involvement in any such recordings.

On closer inspection, the reports, on telephone taps and the secret services respectively, did no such thing. They merely recorded that, in the judges' experience/opinion, stories of secret service involvement were invariably false. Neither report was an investigation of the specific allegations. Yet Downing Street cited them again yesterday in ruling out any new inquiry.

There seem to be three possible explanations for the latest transcript. The first is that it is an inauthentic concoction. That seems unlikely. No one has claimed that either of the other two tapes was invented or falsely attributed. The second is that it was recorded by either of the two parties involved, with the aim of gathering material that would prove damaging to the other party, or helpful to the one who installed the device. That, as several quasi-experts remarked yesterday, is distinctly plausible. The third is that it was indeed picked up by the secret services, possibly as part of some kind of general monitoring of the Royal Family, and subsequently leaked by a maverick element.

Despite official denials, this is far from incredible. A former operative, Peter Wright, revealed in Spycatcher how he had spied on the then prime minister, Harold Wilson, and on the head and deputy head of his own organisation, MI5, and how his colleagues had bugged and burgled their way across London.

What the Government should do is clear. If it does not know who was responsible for the tapes, which were no doubt just the cream of many, it should institute an investigation, preferably in the form of a tribunal headed by a judge. Though much of its proceedings would have to be in camera, the tribunal's conclusions should be published.

Then, whether or not the secret services were involved, the Government should bow to pressure to have both MI5 and MI6 made accountable to a senior committee of parliamentarians drawn from members of the Privy Council. The taxpaying public has a right to know that both the operations and spending of MI5 and MI6 are subject to parliamentary scrutiny. The agencies themselves will benefit, too. Without such supervision they will continue to be the object of similar accusations.