Lawyers, legal groups and academics plan to lobby MPs in a bid to stop Jack Straw pushing through plans to restrict defendants' rights to a trial by jury.
The Home Secretary's enormous U-turn - which will see magistrates deciding whether "either way" cases should go to Crown Court - has been met by outrage across the legal profession.
In 1997 Straw called the same proposals a "massive own goal" because they would lead to lower sentences.
Colette Chesters, a barrister at One Pump Court, has organised a coalition to fight the proposal, winning backing from high-profile silks such as Michael Mansfield, the Bar Council, Law Society, Liberty, Justice and the Legal Action Group.
She says Straw's claims that the measures will speed up the process are "nonsense" since her research shows that Crown Courts list cases for trial around five times faster than magistrates.
She adds: "We don't want to pick a fight. We just want him to talk to us. If the magistrates' court system was fairer, then maybe people wouldn't be so loathe to be tried there."
Franklin Sinclair, chairman of the Criminal Law Solicitors Association, says: "It will decrease access to justice - particularly for ethnic minorities who are more likely to elect to go to the Crown Court - and it might have problems with the Human Rights Act.
"These new proposals are unnecessary and are strictly to do with saving costs," he says.