The Director of Public Prosecutions (DPP) has backed trade union calls for the government to change corporate manslaughter laws after two recent workplace death cases.

Last Friday, construction companies Costain and Yarn were fined £250,000 each for breaching health & safety regulations and must pay costs of £525,000, after a gantry collapsed over the Avonmouth Gorge. Four workers, Paul Stewart, Ronnie Hill, Jeff Williams and Andy Rodgers, died as a result.

Trade and General Workers Union national construction secretary, Bob Blackman, and GMB northern region secretary, Kevin Curran, both called for tougher penalties for corporate killers.

The `not guilty' verdict on 29 November against Euromin general manager Richard Martell also prompted calls for legal change.

Martell was charged with manslaughter by gross negligence over the 1998 death of casual worker Simon Jones at the Shoreham docks.

TUC general secretary John Monks said: "We need a new law on corporate killing so corporate responsibility is clear and the penalties are effective, and we need it as soon as possible."

The DPP David Calvert-Smith QC agreed it needed to be "easier for the criminal courts to bear down on negligent treatment of employees".

He said it was notoriously difficult to prove manslaughter by gross negligence, or "corporate manslaughter", because current laws meant the "controlling mind" of the company had to be identified.