The proposed 60 word caution to be read to suspects is confusing, unfair and likely to cause more miscarriages of justice, say leading criminal lawyers.As the Criminal Justice and Public Order Bill received its third reading in the House of Commons this week, one criminal law specialist called for the Bill to be scrapped, even at this late stage, describing the right to silence clauses as a 'dog's dinner'.The new 60-word caution is not only viewed as potentially confusing to suspects and police officers alike, but also as legally inaccurate.

'The new caution will be of limited use,' predicts Roger Ede, secretary to the Law Society's criminal law committee.

'It is legally inaccurate, misleading and it will not be understood by the majority of people it is given to.'There are four main problem areas with the caution.First, as drafted, the caution informs a suspect that: 'if you do not mention now something which you later use in your defence, the court may decide that your failure to mention it now strengthens the case against you.' Indeed, much of the trouble, according to lawyers, revolves around the use of the word 'now'.For example, at point of arrest in the street, a police officer is not able to question the suspect because the Police and Criminal Evidence Act requires that interviews be conducted in a police station where they can be tape recorded.

But it appears that the caution - with its emphasis on 'now' - might encourage some suspects to volunteer information without access to legal advice.Secondly, under the proposed legislation, suspects are to be given the same caution again when they are charged.

This could mean that suspects might assume they will be penalised for not restating a defence which they might have already provided during interviews.Lawyers point out that legal advisers are not normally present when suspects are formally charged.

One result is that legal advisers may routinely remain in police stations until after suspects are charged - significantly adding to the legal aid bill.Thirdly, the wording of the caution appears to be legally inaccurate.

Criminal specialists point to the phrase which says 'the court may decide that your failure to mention it [a defence] now strengthens the case against you'.This is wrong, said Mr Ede, because failure to state a defence cannot be entered as prosecution evidence.

It can only be brought out by the prosecution during cross-examination of the accused and therefore can only serve to weaken a defence case.

But the language used in the draft caution could lead suspects to conclude that invoking the right to silence will automatically damn them in the eyes of a jury.Finally, the caution is criticised for implying that there is already a case to answer when in fact a suspect is initially only under suspicion.The caution also sparks numerous unanswered questions.

Defence lawyers ask how much detail will suspects be expected to disclose of their defence to avoid adverse inferences being drawn? Likewise, what happens if police questions fail to draw out the defence? Is the suspect then under an obligation to provide information voluntarily?In general terms, point out lawyers, the bill places an obligation on the suspect to make an early defence, but, at the same time, handicaps the suspect from doing so by not obliging the police to disclose fully their information.Mr Ede points out that the Royal Commission on Criminal Justice had recommended that defence solicitors should automatically be given the custody record when called to a police station.

Likewise, Lord Runciman's report said the police should disclose to the suspect and the suspect's legal adviser the nature of the case and the prima facie evidence involved.Neither of those recommendations have been included by the government in the Bill.Lawyers now predict the complexity of the new law will force them to evaluate more carefully each case.

Indeed, the Law Society's criminal law committee has already drawn up a substantial provisional list of circumstances under which invoking the right to silence still will not be the subject of comment in court.