RAF aircraft flown during evacuation of Dunkirk by veteran of the Great Escape had remained buried on Calais beach for decades after being shot down.

An RAF Spitfire once flown by a veteran of the Great Escape and painstakingly restored over five years is expected to fetch up to £2.5m at auction.

The legendary fighter aircraft, dubbed “The Ballerina” because of its grace in the skies, was originally piloted by Old Etonian Peter Cazenove during the evacuation of Dunkirk in 1940.

His plane was shot down by a single bullet on 24 May 1940, and despite radioing in to say “Tell mother I’ll be home for tea!” he crashed landed on the Calais coast and was captured soon afterwards.

While he was then taken to a German prisoner of war camp, his plane was left on the sandy beach in northern France, where it remained buried for decades.

It stayed there undiscovered until the 1980s, when strong tides exposed the smashed aircraft, but it was not until the parts were bought by an American collector and shipped over to the UK that the mammoth task of restoring it began.

Now, the immaculately renovated Mark I Vickers Supermarine Spitfire has been returned to its original glory and is going under the hammer to raise money for charity.

John Romain, pilot and chief engineer at the Aircraft Restoration Company which undertook the restoration project, said the original Spitfire is a remarkable piece of second world war history.

He said: “We have restored it over the last five years. It came to us quite literally in boxes of parts that had been removed from the beach in France. We spent five years restoring it back to its original state – it is unique in that sense.

“We have seen Spitfires at auction before, but many years ago. This one is particularly special, it is very unusual to see a Spitfire like this go to auction. It was a special project for me to be involved in.”

Experts say the plane offers a unique insight into the skirmishes faced by the Allied pilots, and its auction in 2015 falls neatly on the 75th anniversary of the Battle of Britain.

Cazenove, who hailed from a banking dynasty, was taken after his capture to the Stalag Luft POW camp, from where a number of British airmen launched their famous Great Escape in 1944 – immortalised in the Hollywood film starring Steve McQueen. Cazenove’s failure to make it away from the camp probably saved his life.

Romain said: “He got involved in the Great Escape, but luckily for him he didn’t escape that day. Most of his colleagues who did were then shot. He came back to the UK after the war.”

American collector Thomas Kaplan bought the Spitfire’s parts and set experts the mammoth task of restoring it exactly to its original Mark I standards – without the modifications of later versions.

The teams trawled through designs of the plane and rebuilt it to its original form. It is flyable once more and will take to the skies again on 23 May at the Duxford Air Show.

Romain said: “We have restored 18 Spitfires over the years but have never been asked to restore one to such an exacting standard.

“I’ve done the test flying and it was beautiful to fly. It really is a beautiful aircraft. It has flown at Duxford and people there started calling it “The Ballerina”, and that nickname has stuck.

Kaplan said he embarked on the project because he wanted to “enshrine a British legacy”.

He said: “When my great childhood friend, Simon Marsh, and I embarked upon this project, it was to pay homage to those who Churchill called “the few” – the pilots who were all that stood between Hitler’s darkness and what was left of civilisation.

“The upcoming events of 9 July are, more than anything else, concrete gestures of gratitude and remembrance for those who prevailed in one of the most pivotal battles in modern history.”

The Spitfire will go under the hammer at Christie’s in London in The Exceptional Sale on 9 July. It is expected to fetch between £1.5m and £2.5m, and the money raised will go to the RAF Benevolent Fund and Oxford University’s Wildlife Conservation Research Unit.