The son of a war-time hero who survived an infamous massacre, saved a comrade and helped convict the man who ordered it has led dignitaries honouring his memory.

Private Bill O'Callaghan was one of only two men left alive after German soldiers machine-gunned and bayoneted 90 British soldiers who surrendered in the hamlet of Le Paradis, near Dunkirk, in May 1940.

The Dereham resident, who died in 1975, is commemorated by a plaque in William O'Callaghan Place where veterans, family members and councillors prayed, heard the Last Post and observed a minute's silence yesterday morning.

His son Dennis read extracts from Pte O'Callaghan last interview, to German TV, where he recalled his officer saying they were protected by the Geneva Convention despite seeing two machine guns, and then heard the command 'Fire'.

He said: 'I dived down. Then I felt a burning in my arm and I said to myself, 'Good God, this can't be happening', Another of my comrades was lying on my right arm. After some time, the shooting stopped.

'And then I heard what sounded like bayonets being pulled out. They buried the bayonet into the body of a comrade who had moved. Then he was finished off with a couple of shots.'

Pte O'Callaghan lay still and later fell asleep, but was woken by his more badly injured comrade Private Bert Pooley, who he carried to a barn complex several hundred yards away under cover of darkness.

The pair vowed to bring the perpetrators to justice.

Pte O'Callaghan spent five gruelling years as a prisoner of war in Poland, but in 1948 he and Pte Pooley testified at the war crimes trial of Fritz Knoechlein, who was subsequently hanged.

His son described him as a man of few words, but who re-read Cyril Jolley's The Vengeance of Private Pooley every month, and who 'would sleep, but not really, because of his experiences'.

He said: 'When he used to go on pilgrimages and had a drink or two he would talk about what happened, but he would never talk about the shootings.

'I think he would have been proud that his act of bravery is still being remembered.'

He said his father did not bear a grudge against ordinary German soldiers, and together with Pte Pooley had considered sending money to help support Knoechlein's children, but was advised not to.

Rev Sally Theakston, who conducted the service, said that remembering one person helped us remember all serviceman.