A new memorial commemorating the 828 prisoners of war who lost their lives in the Lisbon Maru incident of October 2 1942 includes a soldier whose son now lives in Wheathampstead.

Master Gunner Charles Brooks was drowned in hold number 3 on board the ship during one of the forgotten atrocities of the Second World War, which saw Japanese soldiers firing on POWs to prevent their escape.

The Lisbon Maru was a Japanese freighter which set sail from Hong Kong in late September 1942, carrying nearly 800 troops and 1,816 British POWs to be taken to Japan as slave labour.

As it had no markings to show their presence, it was a legitimate target for allied attack, and on the morning of October 1, it was torpedoed by USS Grouper, as the Americans were unaware there were POWs on board.

After the torpedo attack the hatches were battened down on the three cargo holds where the POWs were crowded in cramped and squalid conditions, and for the next 24 hours they suffered in hot, airless conditions with no food, water, fresh air or latrines, and dysentery was rife.

When the POWs realised their Japanese guards intended for them to go down with the ship and drown, they began to plan their escape. The prisoners managed to break out of the holds just before it sank, but the Japanese troops began firing at them with rifles and machine guns, killing and wounding dozens.

Herts Advertiser: Believed to be the only surviving photograph of the sinking of the Lisbon Maru, taken from a Japanese naval ship around 8am on October 2 1942.Believed to be the only surviving photograph of the sinking of the Lisbon Maru, taken from a Japanese naval ship around 8am on October 2 1942. (Image: National Archives)

As the POWs jumped into the sea to escape the sinking ship the slaughter continued, and only the intervention of local Chinese fishermen, who began to rescue men from the water, caused the Japanese to stop the killing. 828 of the prisoners died from gunshot wounds or drowning.

On October 3, over 650 people attended a service at the National Memorial Arboretum, in Staffordshire, to remember those who died.

The service was attended by descendants of those aboard the Lisbon Maru and representatives of the armed forces and veterans. It was conducted by The Reverend Canon Roger Hall with assistance from The Reverend David Conroy and The Reverend Iain May.

During the service, a new memorial was unveiled by Vice Admiral John McAnally CB LVO, Vice Patron of The Royal Naval Association, who said: “These men did not die in vain.

"Not only did the great gallantry of many individuals save the lives of their comrades but also they like all who fought in the Far East in World War II contributed to development of the Japan we see today: a bastion of democracy in Asia and a country who has resumed her historic relationship of friendship with the United Kingdom.”

“This terrible event has remained hidden and forgotten for far too long,” said Major (Ret’d) Brian Finch, one of the organisers of the memorial.

“The number of descendants who attended the service is a testament to the sense of importance attached to this memorial and the need to ensure that those who suffered and died during the Lisbon Maru incident are remembered.”

Charles Brooks' son Ronald said: "In December 1941 Japan attacked Pearl Harbour and quickly dominated the Pacific area down to the top of Australia, taking control of Hong Kong on Christmas Day 1941, Singapore, the Philippines and Dutch East Indies.

Herts Advertiser: The Lisbon Maru memorial.The Lisbon Maru memorial. (Image: Supplied)

"My mother, brother and I spent the war in Australia after the families of the Hong Kong garrison were evacuated in July 1941. News of the sinking of the Lisbon Maru leaked out to the world in December 1942 but relatives of the POWs had to wait until 1945, the atomic bombs on Japan and the surrender of Japan before learning of the fates of their loved ones.

"By then I was 10 years old and at school in England, my family having returned by convoy before May 1945. We now know that my father destroyed the big guns at Fort Mount Davis to prevent them falling into the hands of the Japanese before the surrender."