Suspects will be forced to play Russian roulette with the law if clauses in the Criminal Justice and Public Order Bill abolishing the right of silence become law.To be debated next week in committee in the House of Lords, the government's proposals would result in neither the suspect nor the legal adviser knowing with any certainty whether a decision to remain silent in the police station will lead the court to infer guilt.

A detailed analysis shows that they may operate unjustly and cause significant confusion and uncertainty in practice.The government argues that a suspect will still be free to choose to remain silent.

But the Bill does not offer the suspect a free choice, as the court may infer guilt from silence.

In addition, suspects may not understand that they cannot be convicted just on an adverse inference.

Their legal advisers will be unable to predict the effect of silence and the police can be expected to continue to persuade some silent suspects to answer questions.Before an adverse inference can be drawn under cl 32, the accused must be questioned or charged with an offence and unreasonably fail to mention a fact which he later relies upon in his defence.A person who is not a suspect or under arrest when questioned may not realise the consequences of failing to respond properly, particularly if the questioning is by a store detective or security officer.The proposed caution an arrested person may receive is unlikely to help suspects understand their legal position:'...if you do not mention something now which you later use in your defence, the court may decide that your failure to mention it now strengthens the case against you...'Even if the interview takes place at the police station, is tape recorded, and the suspect is legally represented, a legal adviser is unlikely to know with any certainty the circumstances in which the court will consider it 'reasonable' for the accused to have remained silent.The legal adviser may consider that the police have failed to disclose sufficient information about the police case or prosecution evidence, or that the police are putting questions or engaging in questioning behaviour which is inappropriate.

But a legal adviser applying Law Society guidance could not be sure that a court would not see matters differently, particularly in hindsight.An adverse inference cannot be drawn under cl 32 until the accused has given evidence.

This means a person cannot be committed for trial or have a case to answer partly on an inference.But the majority of suspects, who are not professional criminals and do not receive legal advice before interview, are not likely to understand the significance of this and the fact that there are circumstances when the accused will not be penalised for remaining silent.There can be no justification for the provision that an adverse inference can be drawn if a suspect fails to mention a fact on being charged.Suspects who were not interviewed are unlikely to know the extent to which they are expected to disclose a defence at this early stage.

They will not know how much detail they are expected to go into since any information they give is not in answer to direct questions.

However, legal advisers will be able to consider whether there is an advantage in advising the suspect to remain silent during interview with a view to making a considered statement on being charged instead.There will be a greater demand for initial legal advice at police stations, and for legal advisers to remain during interview and until the suspect has been charged, and the advice given will have to be more complex than at present.If the legal adviser does not state on tape at the beginning of the police interview that the suspect has been advised to remain silent and the reason for this, the legal adviser may have to explain what occurred by giving evidence (the client having waived privilege).

Or the accused, having realised that a tactical error was made in remaining silent, may transfer legal aid to other solicitors and claim in evidence that he or she was given 'bad' advice by the first legal adviser and should not be penalised for it.Before an adverse inference can be drawn under cll 34 and 35, there must be the finding of an object, substance or mark on the arrested person, or in the place where he is at the time of arrest; or the finding of the arrested person at the place and at or about the time that the offence was alleged to have been committed.The police officer who makes the arrest or carries out the investigation must have a reasonable belief that this may be attributable to his participation in the commission of an offence, specify what the offence is, inform the arrested person about his suspicions, and ask him to account for himself.

The officer must explain in ordinary language what the effect of the law will be if the arrested person fails or refuses to do so.The legal effect of these two clauses is likely to be just as incomprehensible to an ordinary person as cl 32.

Unlike cll 32 and 33, there is no provision to prevent a drawing of an inference if the accused could not 'reasonably' be expected to give an account.

The government has said that there will have to be prima facie evidence of guilt before an inference can be drawn.

But the Bill does not impose such a limitation to cll 34 and 35.The prosecution will be able to ask the court to draw an inference of guilt as part of the prosecution case so that the inference can be added to other evidence in order to make out a prima facie case.

The oth er evidence need be no more than the officer's reasonable grounds for arresting the accused in the first place.The Bill creates problems for the police as well as for legal advisers.

Not only will police officers face allegations of 'non-verballing', when the accused alleges an account was given, but police officers will also not know whether something mentioned by a person at any stage during their arrest, interrogation and detention will later prove relevant to and be relied upon in that person's defence.Officers will have to record every remark which a suspect makes - an unenviable task.

They will also have more work to do, ensuring that questions in interview are asked about all potential lines of defence, and transcribing 'no comment' interviews for trial.It is ironic that cl 33, which allows an adverse inference to be drawn if the accused remains silent at trial, has so far produced the most publicity.

Yet it gives the least cause for concern because at that stage the prosecution case will have been disclosed in full, the accused will normally be legally represented and will have received legal advice about the consequences.