IT was one of the deadliest secrets of the Second World War and even today, Gwent relatives of those who died do not know the complete story. Mike Buckingam reports.
DEATH came literally out of the blue in a storm of cannon shells and rocket fire and within minutes two ships were sent to the bottom and 117 British sailors blown up or drowned.
For years it was thought the fiercest attack against the Royal Navy in the weeks following the D-Day landings had been pressed home by the German Luftwaffe.
"Three Newport and one Risca sailor died in the air attack which most relatives, even 65 years later, thought came from the Germans" Shaun McGuire, a military researcher who's wife's great-uncle who died in the attack and who has no known grave, said.
"Even my own father-in-law who knew most of the details of the incident didn't known until a couple of weeks ago that the British sailors were killed not by the Germans but by the RAF."
There is a nightmarish quality about the deaths on August 27, 1944, a sense of seemingly disconnected errors consolidating into tragedy.
As the sun rose high over the flotilla of British minesweepers all of the Halcyon class including HMS Britomart, HMS Salamander, HMS Hussar and HMS Jason duties were routine enough to allow some of the men to be sunbathing on the decks.
From whence came the warming rays soon was to burst an attack of shattering power from RAF Typhoons so heavily armed that each one said to have the destructive power of a naval cruiser.
"The captain of the Salamander, a Lieutenant Commander King later said that he recognied the RAF planes from their black-and-white indentification stripes" Mr McGuire of Mole Close, Newport, who specialises researching Gwent military deaths said.
"They were circling in the sun and seemed to him to be ready to attack.
"Salamander put out more White Ensigns and Union Jacks and went to action stations but the Typhoon ground-attack planes came on.
"In what we would now call a friendly fire incident the Britomart upon which my relative, Douglas Denham was serving was sunk as was the Hussar.
"Such was the Typhoon's power that the Salamander's stern was blown away and as she drifted under the German guns from where she had to be rescued by HMS Jason.
"It was a mistake of such magnitude that those who survived or otherwise knew of it were told to keep quiet.
"An enquiry - which incidentally exonerated the RAF - was held in secret."
In addition to Douglas Denham the Gwent dead were Raymond Joseph Anthony aged 32 also from Newport and also aboard HMS Hussar and Alan Hugh Jones, 19, of Risca and Leon Kenneth Edgar Jones, 21, of Newport and both aboard the Britomart.
Alan is buried at the cemetery at Cromwell Road, Risca and Leon, who died of his injuries four days after the attack, in St Woolos cemetery, Newport.
The names of both Douglas Denham and Raymond Anthony are inscribed on the Royal Naval Memorial at Plymouth.
An astonishing fact revealed by the board of enquiry is that the RAF pilots, convinced that they had been vectored to attack a friendly force, were three times told to press home an attack.
Even after the aircraft from 263 and 266 squadrons had opened fire and the Squadron-leader in charge of the attacking force had urgently radioed his absolute conviction that the small ships were friendly, he was told to complete the attack.
"Apparently, a Spitfire flown by a Pole had been sent out to reconnoitre earlier that day and had reported the presence of the British vessels but in the wrong place.
"As a result of the report the Typhoons attacked out of the sun.
"Doug Denham who was married with two children Gail and Carol was sun-bathing on the Hussar's deck. His ship and the Britomart went down in the attack.
'My father-in-law Les Williams who is Doug's nephew like scores of other relatives to this day believes the attack was made by German Messerschmitts but that defintely was not the case."
The Risca grave marker of Ordinary Seaman Alan Jones is maintained in pristine condition as is that of his Newport namesake.
Before Remembrance Sunday each year relatives and Royal British Legions members place a tribute of poppies.
"The incident has to be seen against the backdrop of the greatest seaborne invasion the world has ever seen.
"Even so, we can only imagine how the loss of 117 men in one attack would be received today" Mr McGuire said.
"Perhaps the enormous amount of movement at sea, on land and in the air and the vast amount of signals being processed at any one time had a lot to do with it.
"Certainly, no blame was ever attached, certainly not to the RAF pilots who questioned their orders four times.
"But we still have pictures of the men who died and of their ships to remind us that beneath the grave markers and remembered on the memorials are men with familes and stories connecting them to our own time."