Stephen Humphreys of Greenock, Eric Blackley of Gourock and Robert Cameron of Houston died when the tug capsized in thick fog on the River Clyde in December 2007.

The tug's owners, Svitzer Marine Ltd, pled guilty last November and were fined £1.7 million.

The lawyers for the families of the victims today issued a statement in response to the Clydeport plea.

Andrew Henderson, from Thompsons Solicitors, also said the Crown Office must now begin a fatal accident inquiry into the sinking.

He said: “It is very welcome that today Clydeport have admitted their guilt to a series of health a safety breaches. Almost seven years on from the sinking we have to make sure something like this never happens again. The best way to make sure safety on the river is improved is for the Crown Office to begin a fatal accident inquiry into the sinking. There can no more delay on this matter, thousands of men work in the marine industry on the Clyde and the lessons learned from a FAI will help protect their safety in the future.” All three men who lost their lives were members of the UNITE trade union. Pat Rafferty, Unite’s Scottish Secretary, said: “Clydeport’s admission of guilt demonstrates once again the urgent need for Scottish Government intervention to strengthen workplace health and safety legislation.

“By admitting their culpability the law will punish Clydeport with a significant fine but this does nothing for the families of the victims, puts no responsibility on an individual or individuals within the company itself and does nothing to prevent fatalities from recurring in the future.

“Scotland desperately needs a prescriptive legislative agenda that serves to protect working people and their families because from Stockline, the Flying Phantom and offshore helicopter tragedies we are repeatedly seeing the failings of a toothless, protracted justice system.

“We need to radically change the Fatal Accident Inquiry process - something the Scottish Government could have done by fast-tracking the FAI reform proposals made by Patricia Ferguson MSP but failed to - and Corporate Manslaughter legislation should be strengthened to ensure that culpability for workplace fatalities is placed on individual directors within the negligent company itself.

“This will be of little comfort to the families devastated by the Phantom tragedy but given that workplace fatalities in Scotland have increased in the last year it’s clear we need more a robust approach to protect working people.” A Clydeport spokesman said: “In pleading guilty to these three charges, it is important to underline that the Crown accepts these issues were not the cause of the tragic events of December 2007. What these tragic events did do was bring these breaches to light.

“Since this accident we have undertaken a comprehensive restructure of our working practices and systems and welcome the Crown’s comments that ‘the introduction of Work Instruction 19/15 ensures a more robust safety regime for those engaged in towage on the Clyde’.

“The tragic events of December 19th 2007 have been traumatic for everyone involved, particularly the families of the seamen who perished that evening. The legal process has been a long and arduous one, and whilst nothing can bring them back hopefully this judgement can bring a degree of closure to the relatives and workmates of the men who lost their lives.”