Youngest of the seamen who lost their lives in the evacuation of Dunkirk, was John Edward Atkins, from Gravesend, aged just 15.

John was third hand aboard the sailing barge Lady Rosebery. At the outbreak of war his family lived in Shamrock Road, Denton, just outside Gravesend. He attended Gordon School and had always nurtured an ambition to go to sea.

His first voyage did not auger well. He wrote to his mother: “I was near sick for two days. If I get over it, I shall be alright. But if not I’m afraid I shall have to give up the job, but I think I shall get over it.”

The Lady Rosebery traded mostly between the Thames and East Anglia, which proved convenient because John’s brothers and sisters – they were a family of eight children – had had been evacuated to Wymondham, not far from Norwich.

In another letter to his mother John wrote: “We have just left Norwich. Went to see the children on Tuesday afternoon. They are all well except for Ronald, he is under the doctor as he has bad nerves.” Ronald was just two-years old.

Later he writes: “Have seen the kiddies. We are going to Yarmouth, and I think we are north from there for coal. I am sorry to hear that Ron has gone to hospital. I don’t feel like writing as I have just had a winch handle hit me in the mouth and cut all my lips.”

Towards the end of May, Lady Rosebery had orders to head south and report to Dover. She joined 16 other barges moored at the Prince of Wales Pier. Each of the skippers was told that volunteers were needed to cross to Dunkirk to bring back British troops. Not one refused.

While the barge was moored at Dover, John wrote his final letter to his mother. It proved prophetic. “Dear Mum,” it read, “We are under the Navy now. We are going to France today and may never come back.” And then, somewhat unrealistically, “don’t worry”.

Lady Rosebery was one of three barges taken under tow by the Royal Naval tug St. Fagan. The others were Doris, and Pudge. Pudge is still around, under restoration by the Thames Sailing Barge Trust.

Each of the three barges had engines. But they were towed across to save their fuel for the return trip. They were particularly useful because they had flat bottoms and could operate in shallow waters. They could also carry large numbers of men.

“I found myself swimming near two of my men who had been on the bridge with me, and with some little difficulty we managed to reach one of the barges, from where we were taken off by our skiff which had been sent away earlier. We were later picked up by a passing tug and brought to Ramsgate.

Lady Rosebery was blown up and sunk, in an explosion so intense that it lifted Pudge fully clear of the water. It was originally thought that was when John had been killed. The truth turned out to be different.

Two years after the evacuation, John’s mother received a letter from Lieutenant Commander George Warner, who had captained St Fagan on that last fateful voyage. He was prompted to write, having seen an article about John in the Daily Mirror. He told Mrs Atkins that he would not have taken her son across if his barge had been inside Dover Harbour before they set off. But the barges had been outside, so there was no means of getting him ashore. “He was a very plucky youngster and seemed very keen to go,” he said. But added that one of the bargemen had urged him to take John on board the tug, which it was thought would be safer.

“We arrived at our position about 3am,” wrote Lt Cdr Warner. “During the passage across, your son made friends with my seamen, and from the bridge I saw him on the upper deck enjoying the excitement of the air flights overhead and the passing vessels loaded with troops.

“It was too dark to see anyone, so I am unable to say where he was at the time of the explosion. I had hauled the barges up close to the ship and given them instruction, and while they were slipping the tow and getting clear of the ship, we heard low flying aircraft overhead, and shortly afterwards a big explosion occurred, which caused the ship to sink very quickly.

“It is believed that a bomb dropped down the ship’s funnel, so that the end for those below decks must have been instantaneous.

“Of the 26 on board, including your son, only eight were saved. Thus, we lost 18.”

He concluded: “Although the loss of such a promising lad must be a sad blow for you, I trust you will find some consolation in the knowledge that he was assisting in a very valuable job. Please accept the deepest sympathy of myself and his surviving shipmates in such a sad loss.”