The Justice Secretary, Jack Straw, yesterday told the Commons that the Government intends to publish a Bill next week that will allow witnesses who fear intimidation to give evidence anonymously in criminal trials.

But legislation will not achieve the desired objective of ensuring the conviction of the guilty and will only delay the need to consider alternative means of addressing the problem of intimidation.

Last week, the House of Lords allowed an appeal by Iain Davis against his conviction for murdering two men in Hackney, East London, on New Year's Day, 2002. Three witnesses who identified him as the gunman feared for their lives if they gave evidence. They were allowed to testify under pseudonyms, with all particulars of their identity withheld from the defence. They gave evidence from behind a screen, with their voices disguised.

The House of Lords decided that common law prohibited the use of such anonymous evidence because it prevented the defendant from being able to challenge in cross-examination whether the witnesses had a motive for lying or exaggerating. The law lords said that if reform of the law is needed to address the mischief of witness intimidation, it is a matter for Parliament. Other murder convictions are now vulnerable on appeal. An Old Bailey murder trial collapsed this week because of the ruling. Mr Straw said on Wednesday that “there is a difficult balance to strike here, between giving witnesses who fear for their safety the confidence to give evidence in court and ensuring that innocent people are not convicted”.

He is wrong. There is no such balance. The law lords have repeatedly explained that Article 6 of the European Convention on Human Rights confers an absolute right to a fair trial, which cannot be balanced against other considerations, even in relation to measures taken to protect society against terrorism.

The Justice Secretary and Parliament are bound by the UK's international obligations in this respect. Those echo and were strongly influenced by the common law traditions of our legal system, as Lord Bingham of Cornhill emphasised in R v Davis.

Mr Straw's difficulty is that the demands of a fair trial preclude the use of anonymous evidence in almost all circumstances in which it would be crucial to obtaining a conviction. Lord Mance explained for the House of Lords that the European Court of Human Rights regards a criminal trial as unfair where both of two conditions are satisfied. The first is that anonymous evidence is the sole or decisive basis on which the defendant is convicted and the second is where the anonymous nature of the evidence prevents effective cross-examination of witnesses to support the defence case that their evidence should be rejected by the jury.

Other than in the most exceptional circumstances, a defendant who pleads not guilty will be hindered in challenging the evidence of a crucial witness who is anonymous. Defendants will almost always be able to say that because of the anonymity, their counsel was prevented from testing whether the witness had a motive for lying, such as a grudge against the defendant or a link with the deceased.

So any legislation will have to recognise an express exception for cases where knowing the identity of the witness is crucial to cross-examination, or will have to leave it to the discretion of the judge. Either would mean that the police would be unable to guarantee anonymity to witnesses, and judges will regularly refuse applications for anonymity.

The Justice Secretary should think carefully before rushing to Parliament with legislative proposals. An alternative approach, much more likely to be productive, would be to recognise that witness intimidation is not new, and that violent crime has been punished in the past without compromising fair trials. In 70BC, in his prosecution of Gaius Verres for imposing tyranny as the governor of Sicily, Cicero accused the defendant's supporters of “intimidation... to frighten witnesses”. In the House of Lords in R v Davis, Lord Rodger of Earlsferry drew attention to the fear imposed on the East End of London by the Kray brothers in the 1960s, and the longstanding intimidation of witnesses by paramilitary groups in Northern Ireland, neither leading to the use of anonymous evidence.

The second limb of an alternative approach would be to focus on ways to encourage potential witnesses to provide information and give evidence: improved police protection, giving priority to the speedy detection and prosecution of alleged intimidation, and greater police efforts in communities to encourage people to co-operate. As explained in the memoirs of Sir Norman Skelhorn, the Director of Public Prosecutions at the time of the successful prosecution of the vicious Richardson gang in 1967, intimidation may have to be met by the prosecution “relying on criminals or those who had to live by their wits”.

Such alternatives would be time-consuming, expensive and far from ideal. But they would be much more likely to bear fruit than enacting a futile law as a gesture that has no prospect of intimidating judges and lawyers into abandoning the right of defendants to a fair trial.

David Pannick, QC, is a practising barrister at Blackstone Chambers and a Fellow of All Souls College, Oxford

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