In 1940, during the Battle Of Britain, an eight-year-old girl watched in horror as a dogfight between a Spitfire and Messerschmitt played out near her home.

Never forgetting the debt owed by the country to the RAF, 50 years later she began a relentless campaign to prove the identity of, and honour, an unknown airman who died in her village – an effort which will be recognised this weekend at a ceremony attended by his squadron.

When Jean Liddicoat’s 10-year-old grandson, Philip, said he had read there was the grave of an wartime pilot in the churchyard of All Saints Church in Staplehurst, he asked if his nan would help him find it.

She would, and after several hours searching they found the gravestone, almost overgrown, marked simply "An airman of the 1939-1945 war ... Known unto God".

Mrs Liddicoat’s interest was immediately piqued and, recalling the day she saw an airman shot down, was saddened that another hero’s sacrifice should still be unremarked 45 years after the end of the war.

In 1940, standing with her mother near their home in Romney Marsh, they saw the RAF pilot parachute from his aircraft and watched in horror as the German machine-gunned him on his fall to earth.

Determined not to forget the RAF’s contribution, Mrs Liddicoat began a painstaking research of war records to identify the Staplehurst hero, and was eventually after eight years able to determine that the grave belonged to Flt Lt Freddie (Rusty) William Rushmer, who had been shot down on September 5, 1940.

After she presented her evidence to the Commonwealth War Graves Commission, Flt Lt Rushmer’s anonymous headstone was replaced in May 1998, with one properly recording his name and gallantry.

The dedication service, which she organised, was attended by hundreds of villagers and by some former members of Flt Lt Rushmer’s old squadron, and was accompanied by a bugler, and a flypast by a Spitfire and Hurricane.

From the day that she first heard of the grave until her death aged 81 in 2014, Mrs Liddicoat also tended the grave and ensured that it was never again left neglected.

Flt Lt Rushmer had been born to a farming family in Sisland, Norfolk, on April 12, 1910. He was the youngest of 11 children but was the first to die.

He joined 603 (City of Edinburgh) Squadron of the Auxiliary Air Force in 1934 and was called to full-time service with the squadron on August 23, 1939, just ahead of the start of the war.

He was given command of the squadron’s ‘B’ Flight in November and then as an Acting Flight Lieutenant, he was put in charge of the 603 detachment at Montrose, where it was engaged in convoy protection duties.

On January 19, 1940, he damaged a Heinkel He111 bomber and in March his promotion to Ft Lt was confirmed.

On July 23, he shared in the destruction of a Dornier Do17 bomber; on July 30 he shared in destroying another He111 although his aircraft was hit by return fire.

He was then transferred to Hornchurch to join in the Battle Of Britain. On August 29, he was obliged to make a forced landing at Bossingham after he was slightly wounded in combat over Deal. He was soon back in the air and on September 3, he destroyed another Do17.

But just two days later, he failed to return from combat with Do17s and Bf109s over Biggin Hill and was reported as missing.

That day, a Spitfire crashed at Buckman’s Green Farm in Smarden and the body was beyond recognition. The pilot was buried as ‘unknown’ in All Saints’ churchyard, Staplehurst.

At this crucial period at the height of the Battle of Britain, there was little time for a thorough investigation.

An excavation of the crash site in 1970 still failed to determine the identity of the pilot, but did unearth a half-hunter silver pocket watch, with its mechanism stopped at 10am, the moment of impact.

Starting her research 20 years later, Mrs Liddicoat determined that on that fateful day, a Thursday, eight RAF pilots had been shot down over Kent, and only six identified. She then had two possible names for the Staplehurst airman.

She was able to get hold of the recovered watch and determining that three of Flt Lt Rushmer’s sisters were still alive, she went to visit them in Norfolk. His sister Margaret, by then aged 92, was able to positively identify the watch as one that had been given to her brother on his 21st birthday.

In 1999, 603 Squadron was reformed and Mrs Liddicoat travelled to Scotland to tell them about their fallen comrade. Ever since, she has been held in high regard by the airmen for her work in identifying one of their own and they even made her an honorary member of the 603 Squadron Association.

After her death, Mrs Liddicoat’s husband Desmond, who was the verger at All Saints, continued an association with the RAF, even using his 90th birthday as an opportunity to raise money for the RAF Benevolent Fund.

Now aged 92, he lives in a local care home

The couple had three sons – Stephen, Christopher and Michael – and a daughter, Jeannette.

Sadly Stephen predeceased his mother.

Christopher Liddicoat still lives in Staplehurst, and his grown-up daughters Claire and Ellena now care for Flt Lt Rushmer’s grave as well as their grandmother’s.

On Sunday (September 10) serving and former members of 603 Squadron will travel to Staplehurst from Scotland to join in the village’s annual Battle of Britain memorial service at 10am.

After the service, there will be a dedication at Flt Lt Rushmer’s graveside.

The RAF has obtained special permission from the Commonwealth War Graves Commission to lay a small plaque next to Flt Lt Rushmer’s headstone recognising Mrs Liddicoat’s untiring efforts in proving his identity.

Her son Christopher said: “My mother was a very determined lady. On one occasion someone told her she would never get the airman a proper headstone.

“Of course, after that, there was no way she was ever going to give up.”