The decision this week to halt a murder trial at the Old Bailey follows a ruling on June 19 by the House of Lords that granting anonymity to witnesses threatened with intimidation could render a trial unfair. An accused, they said, had a right to confront his accuser. The ruling came in the case of Iain Davis, who had been convicted in 2004 of a double murder of two men at a New Year's Eve party in Hackney, East London. He can now seek to have his conviction quashed. Seven witnesses in the case had claimed to be in fear of their lives if it became known that they gave evidence against Davis. In this piece, Davis's barrister argues that the law lords were right.

"The right to confront an adverse witness is basic to any civilised notion of a fair trial. That must include the right for the defence to ascertain the true identity of an accuser where questions of credibility may be in issue."

So said in 1986 a judge who would go on to become head of the New Zealand Court of Appeal. After those prophetic words were uttered, our courts began to descend that slippery slope. Witness anonymity became one of the means employed to satisfy the driving need to convict those accused of crime. The end justified the means.

It was to expected that the police would react to the law lords' decision in the Iain Davis case last week with scaremongering and calls for emergency legislation. It is also to be expected that this Government will, as always, pass some knee-jerk measures designed (if that is the right word) to reverse the effect of the ruling.

It is surely time to step back and reflect in a mature and careful way on whether anything can or should be done to alter the common law in so fundamental a manner as to deny the accused knowledge of the identity of his or her accuser.

Throughout history, attempts have been made to deprive the accused of this right, even though it is fundamental and a prime protection against unfairness. From time to time, judicial systems have succumbed to the temptation to curtail or to extinguish it. The temptation is usually borne of expedience and driven by a desire to assert some perceived need to protect the accuser. But the accuser is not on trial.

As soon as an accused is denied knowledge of the identity of his accuser, he is effectively handed the almost impossible burden of proving that a witness does not deserve the protection of anonymity but without the knowledge required in order to do so.

Witness anonymity invites perjury and insulates the perjurer from detection. The defence cannot test the witness’s credibility and reliability through investigation or effective cross-examination. The accused is denied access to the reputation of the accuser in the community; oblique motives and bias can never be ascertained; prior inconsistent statements to third parties cannot be discovered: prior relationships with the victim or with the accused remain hidden.

The law lords' ruling does not change the law in any way. It merely re-asserts a long-standing common law right which had been gradually undermined in recent years by claims for anonymity for witnesses who were (sometimes understandably) apprehensive about giving evidence. Many said that they feared intimidation or retaliation. The fear expressed usually assumed the guilt of the accused. The genuineness of those fears could never of course be tested.

The public may not appreciate that police applications for witness anonymity were conducted in conditions of secrecy. Prosecutors and policemen were able to see judges privately in the absence of defence representatives, to persuade Judges to grant anonymity on the basis of information that could never be verified or tested and to withhold any information from the defence that might tend to identify the witness.

In practice that meant that the accused would have little material with which to test the veracity of the witness and none with which to test credibility or motive to lie.

Contrary to the suggestion of the Assistant Commissioner of the Metropolitan Police, the ruling does not change in any way the use of special measures to protect witnesses. Witnesses may still have pseudonyms, screens, TV links, voice distortion and so on. The ruling simply means that the defendant must know the identity of his accuser in order to challenge the evidence effectively. That is common sense, not merely the common law.

The suggestion that inroads into the common law should be made because of a perceived increase in gun crime demonstrates the fallacy of the argument. Fundamental principles should never be sacrificed to expediency. The incidence of gun crime in the UK may be thought to pale beside past terrorism in Northern Ireland and in South Africa, genocide in Rwanda and in the former Yugoslavia and organised gang crime in the USA or in New Zealand. In none of those jurisdictions has it been thought necessary to deprive the accused of knowledge of the identity if his accuser. Instead, the witnesses are protected either by effective witness protection programmes or by controlled statutory exceptions to the common law right or both.

There are perfectly adequate and proper methods of protecting witnesses without hiding their identities. Those methods include setting up formal witness protection schemes, informal methods of providing protective surveillance and accommodation to witnesses, relocating witnesses and/or providing them with a new identity after the trial (some of these methods are already employed in the UK), and delaying disclosure of the identity of witnesses until the latest possible stage in proceedings where that is consistent with the rights of the accused.

Legislation that does not preserve the defendant’s confrontation rights, particularly his right to effective cross-examination, will be incompatible with Article 6 of the European Convention of Human Rights. Legislation may follow the New Zealand model, which attempts to define the exceptional circumstances in which anonymity may be permitted: (i) there must be no reason to believe that the witness has a motive or tendency to be untruthful, (ii) it must be possible to test credibility properly, and (iii) the accused must not be deprived of a fair trial (all of which in reality and in practice preserves the common law rule).

Another candidate is the model adopted by the International Criminal Tribunals and the International Criminal Court, which permit witness anonymity in the preparatory stages of the trial process but insist on disclosure of identity in sufficient time before trial to allow adequate preparation for cross-examination.

Let us hope that the Government does not legislate in haste only for society to repent at leisure.

The author acted for Iain Davis, the appellant in the House of Lords case last week

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