FAMILIES of the victims of the French crew members killed after their trawler was believed to have been dragged down by a nuclear submarine have been told by investigating judges that navies, whose subs were playing wargames off the Lizard at the time, hid behind official secrets red tape and only gave judges documents that suited them.

The judges' accusation came in an apologetic letter of explanation formally addressed to 20 relatives of the crew of the Bugaled Breizh.

It was signed by one of the judges on a panel which finally ruled that a nuclear attack sub which snagged the trawler's cables was the "most probable" culprit.

The panel of judges has been unable to identify the guilty submarine which could lead to charges of manslaughter and failing to assist persons in danger.

In a five-page document seen by the families as an admission of defeat, the judge explained to the families how the navies of Britain, France, Holland and Germany behaved, revealing that: "In five years of investigations we have only been able to establish the positions of 12 submarines."

Judge Melanie Gehin put the failure of the investigation down to two reasons, telling the grieving families: "Firstly the activities of submarines which are called upon to carry out missions requiring the utmost discretion are hidden by official secrecy rulings which cannot be systematically lifted.

"Secondly, concerning investigations taking place in foreign countries, powers of investigating judges are limited to requesting information from authorities abroad who are free to answer in any way they wish".

The letter does not specifically name the Royal Navy but clearly points an accusing finger at defence ministries of countries whose submarines took part in the Thursday War exercise on January 15, 2004.

Madame Gehin continued: "It seems obvious that the country's submarine which was involved in such an accident would take care not to supply proof of its involvement to the French authorities".

In the same letter the judge repeated the investigators' conviction that only a nuclear-powered submarine would have had sufficient power to drag the Bugaled Breizh down in less than a minute.

Madame Gehin cited four navies as operating nuclear submarines – the United States with 48, France with five, Britain with four and Russia with 15.

She gave the families formal notice of her court's refusal to request the four navies to reveal positions of their nuclear subs at the time of the accident, citing the navies' policies on official secrets.

Angry relatives of the dead crew called "the navies' lies" despicable last night and again called on them to "come clean and give us some truth about what happened to our men".

In the past they have cited the Royal Navy in particular, accusing it of "hiding the truth" about the Bugaled Breizh.

Meanwhile, they are waiting a judgment by a higher court in the Breton capital Rennes next month, at which it is widely expected that judges will an announce an inconclusive end to the five year French investigation.

Later this year, or early in 2010, a British inquest into the deaths of the Bugaled Breizh will be resumed in Cornwall.