The controversial proposals were outlined in the Queen's Speech setting out the government's legislative programme for the year ahead. It will include two flagship law and order bills.

The Crime and Probation Bill will introduce far-reaching change in the probation service, giving probation officers greater enforcement powers.

The BBC's Niall Dickson reports: "Ministers plan to restrict the right to tral by jury"

The bill will allow compulsory drug-testing not only of offenders but also people who have been arrested but are unconvicted of any offence whatsoever.

Attack on civil liberties

Liberal Democrat home affairs spokesman Simon Hughes was quick to brand the changes a "serious erosion of our civil liberties".

He said: "The proposed change to the right to trial by jury in England and Wales is a dangerous weakening of civil rights putting economic savings before the quality of justice.

"And any large scale expansion of mandatory drug testing of suspects, no matter what the circumstances, would not only be wrong but highly unworkable."

While head of the civil rights campaign group Liberty John Wadham said, "any proposals for a blanket approach to drug testing must be resisted at all costs.

"Empowering the police to forcibly test anyone they've arrested for any offence to find out whether they've taken drugs would raise some serious questions about what kind of society we want to create."

Plan previewed at party conference

Prime Minister Tony Blair with Home Secretary Jack Straw at Labour's party conference this autumn

The measures allowing compulsory drug tests on offenders or people under arrest were previously announced by Prime Minister Tony Blair at Labour's conference in October.

The government says the tests will be targeted at offenders who turn to crime to fund drug habits, including high-level heroin and cocaine users who could be refused bail if they test positive.

The results will also be used to channel drug misusers into treatment programmes, to monitor offenders under probation service supervision and to support a new drug testing community sentence.

A new criminal offence will be created to stop people who have been identified as unsuitable, either because of previous convictions or because of their past behaviour, from ever working with children.

The crime would cover the public, private, voluntary and volunteering sector and is aimed at stopping paedophiles continuing abuse by changing jobs or moving house.

Ancient jury right scrapped

The Criminal Justice (Mode of Trial) Bill will scrap the ancient right of defendants to elect trial by jury.

Under the bill, it will be left to magistrates in England and Wales to decide where middle-ranking offences - which can currently be heard either before magistrates or at crown court - should be tried.

So-called "triable either way" cases at the moment include theft, assault and some drug offences.

Magistrates will be able to take into account whether the defendant has previous convictions, and will be told to take account of the effect of convictions on a defendant's reputation and livelihood.

Defendants would have a right of appeal to the crown court against any decision to try the case themselves.

According to figures published this week, axing the right to choose jury trial could save millions of pounds a year.

But lawyers have condemned the plans as an attack on justice likely to hit black people and minorities in particular, many of whom had little confidence either in the police or of getting a fair hearing before magistrates.

'Two-tier system' warning

The bill is expected to affect around 18,000 defendants a year.

Chairman of the Bar Council Dan Brennan said Home Secretary Jack Straw had got it right when in opposition when he condemned any restriction on the right to trial by jury as "wrong, short-sighted and likely to prove ineffective".

Mr Brennan said: "It will create a two-tier system of justice with middle-class defendants given privileged access to the crown courts if magistrates decide they have a reputation to defend.