A PORT operator has admitted health and safety failures fo­llowing the sinking of a tug boat in the Clyde in which three men drowned.

Clydeport Operations Limited had denied culpability over the deaths of Stephen Humphreys, 33, Eric Blackley, 57, and Robert Cameron, 65. They were crew members on The Flying Phantom which sank in December 2007 when it was overtaken by the cargo vessel it was towing in heavy fog, causing it to capsize.

However, the firm yesterday admitted failing to have in place an adequate contingency plan if fog was encountered, especially when a large vessel was being towed. It also admitted failing to provide a safety management system and to appoint a suitable individual or individuals as the designated person.

The owners of the tug boat, Svitzer Marine Limited, had pleaded guilty to health and safety charges last year and were fined £1.7 million after their breaches were found to be the primary cause. The firm failed to act after a previous incident involving the same tug in December 2000.

Andrew Henderson of Thompsons Solicitors, who represents the victims' families, said: "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 an FAI will help protect their safety in the future."

The hearing, at the High Court in Edinburgh, was told that, while Clydeport had admitted failures, it had been Svitzer that had been the "significant cause" of the deaths.

Richard Keen, QC, counsel for Clydeport, told Lord Kinclaven that when Svitzer pleaded guilty it was on the express basis that its breaches of duty had caused the "girting" and sinking of the tug.

He added: "A review, an ­investigation of Clydeport's systems, discloses it could and should have done things better. There are no aggravating features here, such as a party being told they are not doing it right and then doing nothing about it."

The Red Jasmine bulk carrier, which The Flying Phantom was towing, was the largest ship to have visited the Clyde for decades. It was carrying animal feed from Brazil and was due to arrive in Glasgow's King George V dock.

Conditions had been good but as the ship made its way upriver it encountered fog. The Flying Phantom radioed the pilot of the Red Jasmine saying it had run aground and was told to let go of the line. The tow release button was pushed but the vessels were not disconnected quickly enough, causing The Flying Phantom to be capsized by the vessel it was pulling.

The bodies of skipper Mr Humphreys, from Greenock, Mr Cameron, from Houston in Renfrewshire, and Mr Blackley, from Gourock, were later recovered. A fourth crew member, Brian Aitchison, survived.

A Clydeport spokesman said: "In pleading guilty to these three charges, it is important to underline the Crown accepts these issues were not the cause of the tragic events. 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.

"The tragic events ... have been traumatic for everyone involved, particularly the families of the seamen who perished that evening. While nothing can bring them back hopefully this judgment can bring a degree of closure to the relatives and workmates of the men who lost their lives."

Sentencing, in which Clydeport is expected to receive a heavy fine, is to take place on Monday.