Unions have vented their anger amid speculation that long-awaited legislation on corporate killing has been left out of tomorrow's Queen's Speech.

The Home Office is now expected to introduce only a draft Bill on changing the law.

Officials said this would meet Home Secretary David Blunkett's commitment to publish proposals before the end of the year.

But MPs, trade union leaders and Sussex campaigners who fought for a change in the law following the death of Simon Jones, killed hours after starting work at Shoreham harbour, will be disappointed.

Tony Woodley, general secretary of the T&G union, has written to Tony Blair and all MPs protesting at the delay.

He described the Queen's Speech as the "best and last chance for the Government to create a robust and effective law".

"Bosses are getting away with murder and will continue to do so until they realistically face the prospect of jail.

"Fines are falling whilst deaths are rising, as the existing law fails workers and their families," he said.

Mr Jones, a student at Sussex University, died when his head was crushed by an excavator grab in the hold of a ship in April 1998.

The 24-year-old's family fought for more than three years to bring Euromin and its British operations general manager Richard Martell to court. The firm and Mr Martell were acquitted of manslaughter.

But the company was fined £50,000 for violating two Health and Safety regulations at its wharf in Shoreham harbour in 1998.

Campaigners, led by Mr Jones' mother Anne, have repeatedly argued managers must not be allowed to claim they were ignorant of what was happening in the workplace.

Mr Blunkett promised to publish proposals on changing the law in May.

But the Government has yet to decide when the legislation will be enacted.

The Home Office is understood to be reconsidering its definition of what should trigger corporate liability. It said the delay did not mean the proposal was doomed.