Defence lawyers yesterday backed Grossman as legitimately raising the issue for debate, but the remarks, placed in a widely used and respected legal text, angered both the judiciary and the Department of Justice, which argued that Grossman came to a wrong conclusion from a poor understanding of the statistics.

'[The preface] is understandably widely perceived to be an attack on the impartiality of the judges in the administration of criminal justice. The Chief Justice believes that such an attack is totally unjustified and wholly misconceived,' a judiciary spokesman said. 'In the Chief Justice's view, the preface lacks objectivity and falls well below the proper professional standards to be expected of a preface to such a well-known text. The Chief Justice considers that it is an ill-considered and intemperate outburst by the author.'

In the preface, Grossman noted that the latest yearly report by the Director of Public Prosecutions cited conviction rates of 94.8 per cent in the Court of First Instance and 92.6 per cent in the District Court last year.

These rates meant that 'any person who is arrested on a serious or relatively serious charge is almost certain to be convicted and since the convictions are in the District and High Courts, imprisonment is almost always the norm', Grossman wrote.

'I am not sure whether the Hong Kong statistics are stated as deserving of a pat on the back but if so, such pride is most certainly misplaced. I would suggest that this almost universal conviction rate should be a matter of concern, not only to lawyers but more particularly, to the public at large,' he wrote.

Grossman went on to describe the Department of Justice as being a 'notional filter' that had no incentive to screen out weak cases 'given the near certainty of obtaining a conviction'. He concluded: 'The high rate of convictions, (probably approaching that of North Korea) is founded on the comforting assumption that prosecution witnesses, including the police, ICAC and especially accomplices and other immunised witnesses, whatever imperfections may be apparent in their evidence, always tell the truth!'

Yesterday, he acknowledged that his comments, the first time the preface to Archbold has been used to spark public debate, were controversial but said the issue was a concern among lawyers working in criminal law.

'I'm not saying the judiciary is not impartial, but the rates have been a concern for some time, and they keep getting higher. I'm pretty sure that all those doing criminal work at the Bar will agree with me,' he said.

Indeed, one lawyer who did not wish to be named said it was 'marvellous' that the issue was finally being raised for public debate. He said many lawyers felt disheartened to be always fighting battles when they knew the result would almost certainly be a conviction.

However, Director of Public Prosecutions Grenville Cross SC said: 'It is incongruous that comments of this type should have appeared in a preface to a reputable legal textbook.

'What the author seems not to have appreciated is that the figures quoted for convictions in the Court of First Instance and the District Court are overall rates, covering both guilty and not guilty pleas, and that reasonable conviction rates are a pointer to the fact that only the cases which should be prosecuted are being prosecuted.'

Another senior lawyer in the Department of Justice said that when guilty pleas were removed from the statistic of 'convictions' the rate last year fell to 73.3 per cent in the District Court and 79.3 per cent in the Court of First Instance. 'We are a legal oasis in the region and to compare us to North Korea is just silly,' he said.

According to Britain's Crown Prosecution Service, the government department responsible for prosecutions in England and Wales, the conviction rate for the crown courts in the 2008-2009 financial year was 80.9 per cent. However, when guilty pleas, which account for 73.2 per cent, were removed from the equation, convictions after trial were 7.7 per cent.

The judiciary spokesman noted that Grossman had notified a permanent judge of the Court of Final Appeal that his comments were 'not intended to impugn the impartiality of the judiciary in the administration of justice'.

Nevertheless, the spokesman said the Chief Justice still felt 'it is a matter of great disappointment and regret that such an ill-advised preface has been written and published'.

Simon Young, director of the Centre for Comparative and Public Law, said reference to conviction rates alone was not useful. More valuable was data on the number of cases being screened out by the Department of Justice as a measure of its performance.

'You could equally say that only the strongest cases are going to court and that the department has a good screening process. If a lot of cases are being screened out, then you would expect a high conviction rate,' he said. 'If there are few cases being screened out, but you still get a high conviction rate, then perhaps you should worry.'

Young called for a review so that more revealing data could be collected.