The introduction of compulsory drug-testing before suspects have been found guilty of an offence will meet stiff resistance from civil liberties groups. Jack Straw compared it to compulsory drug screening for prisoners. But it is the first time any Government has proposed compulsory testing before cases have reached court.
Mr Blair took the unusual step of leaking the announcement from his keynote speech to the conference tomorrow in a BBC Breakfast with Frost interview, which raised suspicions that the crackdown on drug crime was being used to quash speculation over weekend claims - denied by Mr Blair - that he wanted to go on for three terms of office, as Margaret Thatcher did.
"People are petrified about drugs," he said. "I am petrified about drugs in respect of my own children and other people's children. I will be saying on Tuesday in the Queen's Speech there will be a crime and justice Bill and drugs will be the main focus of it. We will be looking at some of the key issues that we just ducked - all governments - for far too long."
The Home Secretary said there was a huge disturbing link between drug users and crime. There were an estimated 100,00 to 200,000 problem drug users in England and Wales and each would commit scores of crimes to feed their habit.
The tough action will be seen as an admission that the Government has failed to curb drug-related crime. It also means Charles Kennedy, the Liberal Democrat leader, will be isolated in calling for a royal commission to review de-criminalising cannabis.
Mr Straw firmly rejected that and said voluntary testing suggested half of all those arrested had taken drugs recently. Officials said most of the 61 per cent who tested positive in trials in Manchester, London, Sunderland and other cities had been taking cannabis, but 18 per cent tested positive for heroin and 10 per cent for cocaine or crack.
John Wadham, director of the civil rights group Liberty, said: "These proposals are wrong in principle and risk breaching the European Convention on Human Rights.
"The link between drugs and crime is problematic and needs to be broken but eroding rights won't crack crime and this approach misses the whole point - which is to stop people becoming problematic drug users in the first place."