A rare bravery medal earned by one of Norfolk’s greatest heroes of the country’s worst post-war flood disaster is set to be sold to the highest bidder - six years after its shock appearance in an auction saleroom sparked a police investigation.

Yarmouth fireman Fred Sadd was presented with the George Medal - the nation’s second highest civilian gallantry award - for saving 27 men, women and children trapped in their homes when a North Sea surge devastated the East Coast in January 1953, leaving more than 300 people dead in its wake.

But more than six decades later his remarkable story was headline news again in very different circumstances when the award, which had been loaned for display at the town’s fire station, turned up in a Suffolk auctioneer’s sale catalogue.

Seized by police, it was subsequently returned to the hero’s son and daughter-in-law, Brian and Brenda Sadd, though a year-long enquiry closed with no one facing prosecution.

Now the couple, who are both in their 80s, have made the “difficult” decision to sell the medal, along with a family treasure trove of documents and photographs that includes a 10 shilling note sent in a letter of thanks by an anonymous Londoner in the immediate aftermath of the floods.

Speaking at his Great Ormesby home ahead of next month’s Spink auction, Mr Sadd explained: “We’re both getting on a bit and we haven’t got any children to leave them all to, so we felt the time had come to let them go to someone who will look after them and take as much pride in them as we have.”

Conservatively valued at £4,000-£5,000, the prized possessions, which include a wartime Defence Medal and Fire Brigade Long Service and Good Conduct Medal, are expected to fetch a much higher price when they go under the hammer on November 24.

Predicting a “feeding frenzy” from collectors in Britain and abroad, Spink’s head of medals Marcus Budgen said: “Not only is the story of the George Medal truly amazing, the circumstances behind it are extremely rare. We’re lucky that in this country we don’t have many natural disasters of this kind and that makes Fred’s award highly unusual and highly emotive.”

He said that he felt privileged to be able to memorialise the story on behalf of Fred's family. “He was such a brave man, and modest to a fault,” he added. “He worked at saving lives until he quite literally dropped from exhaustion. And on a night when the level of courage required to earn a George Medal was incredibly high his actions were amazing. It’s one of the most outstanding awards of its kind that we’ve ever handled.”

The upcoming auction represents the latest twist in an extraordinary saga of courage cloaked in a still unresolved modern-day ‘whodunit’ mystery.

The strange odyssey of Fred Sadd’s George Medal began two years after his death in 1987 at the age of 77 when his hard-earned honour was loaned to Yarmouth Fire Brigade.

“As well as being a memorial to my father,” said Brian, “we thought it was something the whole town could take pride in and were pleased to think it would be publicly displayed with his other medals for the benefit of everyone in Yarmouth.”

For security reasons the distinctions were later replaced by replicas and the originals put in a safe before being moved to another fire station.

“We used to sit here thinking they were in safe hands with the fire brigade,” said Brenda, “until one day in 2015 I went to the local paper shop and saw the headline, ‘Flood hero’s medals to be sold’. It was such a shock. I remember running home in tears and saying to Brian, ‘They can’t do that!’”

Shock turned to anger when they discovered that the original medals had vanished years earlier and been sold perhaps as many as three times before ending up in an Ipswich auction room.

According to the subsequent police investigation, they had apparently been “stolen” from the Fire Brigade before being traded into the hands of private collectors.

“It was unbelievable,” said Brenda. “If medals could talk, what a story they’d have to tell. We thought they were safe when, in fact, they were passing from person to person. And if it hadn’t been for that newspaper story we’d never have known.”

Now, with the medals and their associated papers about to be sold legitimately for the first time, the couple have one final wish. “Whoever ends up buying them,” said Brenda, “we just hope they will be treated with the respect they deserve in honour of a very brave man.”

In a personal note accompanying the sale entry, she added: “His actions in the floods of 1953 were so typical of him. The word hero is unfortunately very over used now, but he was one, a real one, and I hope he will be remembered as such.”