Bognor a haven after Frank's incarceration

But the truth is that he probably never got over the torture and solitary confinement he endured as a prisoner of the Germans.

Frank, who lived with his wife in Bognor throughout the 1920s, was a man scarred by the conflict, as his grandson Dale le Vack recalls.

Dale was born in 1946; Frank died in 1968.

"He introduced me to fishing in the 1950s, and he used to tell me about his experiences when I was a child."

Dale has now used them to write part of his life story in fictionalised form: "I remembered enough of those stories and did the research to check them against the historical facts.

"He was a very tall man with a mellifluous voice, a very well-spoken man with a deep voice. He was always very polite, always very modest."

The book is published under the title Not Quite The Gentleman, a reflection of the fact that when Frank went for a commission in the army in 1909, he was turned down, being neither gentry nor aristocracy.

But he was still determined to serve his country and entered the army as a private.

He fought with the 1st Battalion, Norfolk Regiment at the Battle of Mons in August 1914 and led a bayonet charge.

"Frank was an ardent diarist but lost the accounts of his early life, including war service and captivity as a prisoner-of-war when the family house on the Norfolk Broads was flooded in the 1930s. After he married in 1919 the family moved to Bognor Regis where he started to write his life story. I was persuaded by a family member to recreate the years 1883 to 1919 and to represent it as a novel."

"It took me nearly three years to write this book and during that time I got to know about a man who otherwise would have remained just a shadow in my memory. It was through the writing that I got to know him adult to adult rather than boy to adult as we were then, and I got to realise the incredible impact incarceration must have on a human being.

"Fishing was his great solace, his tranquillity, but you can't overestimate what effect incarceration must have had. He did in later life try to settle down, but he was never really able to do that."

Wounded on the battlefield, Frank was left behind by the retreating 1st Battalion Norfolk Regiment. Lying close to death in a field, he evaded capture on the battlefield in Belgium and was found by a young nun whose convent had links with the Edith Cavell escape network.

"He was captured in 1915 and was finally released early in 1918 under a repatriation scheme for the long-term prisoners. They sent him to Holland."

After his capture, the interrogation was harsh. Frank was subjected to a form of torture known as the pole: "You are lashed to a pole with your feet just on the ground so that if you start to try to move, you start to choke. He managed to survive several bouts of that. He safeguarded his sanity by his fishing diaries and his memories."

It's a story which appeals to Dale's 14-year-old grandson Louie Webb in Worthing, a pupil at St Andrews Boys School - particularly in its relation to cricket. It turns out Frank may have been one of the early exponents of reverse swing, says Dale, who lives in Stratford-upon-Avon.

Selected to play cricket in an important cup match against the Cavalry for 15th Infantry Brigade before the war, in June 1914, Sergeant Frank W Clarke opened the bowling. Eventually he got the wicket of the opposition's star batsman, to win the game by one run - apparently by using a form of reverse swing.

Not Quite the Gentleman (Original Writing, Dublin) ISBN: 978-1-907179-28-0 (15.99). The book is available by order from bookshops in Sussex or the publisher's electronic bookshop. Original Writing Ltd is based at the Spade Enterprise Centre, North King Street, Smithfield, Dublin 7, Republic of Ireland.