A SOLID gold egg made as part of a nationwide competition run by Cadbury's 30 years ago has been sold for thousands of pounds at auction.

The three-inch tall, 22-carat egg was one of 12 commissioned by the chocolate maker in 1983 for its Crème Egg Mystery Conundrum.

Cryptic clues contained in a specially published book guided treasure hunters to secret locations around the country where caskets were buried, each containing a certificate entitling the finder to one of the prized eggs.

One of the caskets was buried in the grass verge of the A66, west of Bowes, County Durham.

Its whereabouts was uncovered at the time by a local resident who, 30 years later, decided to sell his prized possession with the help of Barnard Castle-based antiques expert David Harper.

Mr Harper put the egg forward for sale at Frank Marshall Auctioneers, in Knutsford Cheshire, where it was bought by a telephone bidder for £6,000.

Mr Harper said his client, who wishes to remain anonymous, would be pleased with the result.

“We had lots of interest in the egg. The buyer will be happy and the seller will be delighted it made all the money it was worth.

“It could not have gone to a better market place – in an ordinary sale, it may have sold for just £2,000.”

Bidding opened at £4,400, well below the £6,000 estimate, but bids gradually built up.

Mr Harper added: “I wasn't nervous. The auctioneer will always slowly and build up the momentum.”

The egg was made by Garrards, jewellers to the Queen and was called The Burning Hand for the Cadbury's promotion. It was number ten of the 12 made for the competition.

The event proved so popular it had to be called off before all the caskets had been found after thousands of people started digging up private land and historic sites.

Many people thought the County Durham clue led them to the grounds of Bowes Castle.

At the same auction, Mr Harper – a well-known face on BBC shows such as Bargain Hunt and Antiques Road Trip - put forward 25 pieces of original artwork depicting the covers of 1950s adventure books, many incorporating cowboys and indians, for another of his clients.

“He worked for the publisher and was given them as a gift. Again, there was an awful lot of interest in them, especially the action covers.”

Each piece of art was estimated at between £100 and £300.