A royal fan has told of his delight after buying a slice of the Prince and Princess of Wales’s wedding cake for £1,850 at auction – more than 40 years after Charles and Diana tied the knot.

The large piece of cake icing and marzipan base from one of the 23 official wedding cakes features a sugared design of the royal coat-of-arms coloured in gold, red, blue and silver.

It was given to Moya Smith, a member of the Queen Mother’s household at Clarence House, who preserved the topping with cling film.

She kept it in an old floral cake tin and taped a handmade label to the lid, reading: “Handle with Care – Prince Charles & Princess Diane’s (sic) Wedding Cake”, which she signed and dated 29/7/81.

Mrs Smith’s family sold the cake in 2008 to a collector, but it came up for auction again this year, coinciding with what would have been the Waleses’ 40th wedding anniversary on July 29.

The cake went under the hammer at Dominic Winter Auctioneers in Cirencester, Gloucestershire, on Wednesday afternoon, and was expected to fetch between £300 and £500.

But a flurry of bidding from across the world led to an internet buyer securing the slice for £1,850.

That buyer was Gerry Layton, of Leeds, Yorkshire, who charters a boat providing luxury tours of the River Thames in London.

“I have always been a monarchist and I had been to see the wedding dress at Kensington Palace,” Mr Layton told the PA news agency.

“I did some research and this auction for the cake came up. I looked up the auction house and part of the postcode was the same as a car registration that I own, so I thought it could be fate.

“I thought I would like to add it to my estate, which will be going to charity after my death.

“I hope to be here for a long time but the virus prompted me to make a will. I have 25 charities listed in my will.

“I also thought that I could put it up as a raffle prize with some of the money going to Centrepoint, which Princess Di was patron of.

“I will have to think of a way to stop myself from trying to eat it though.”

Mr Layton said he planned to make the trip from Yorkshire to Gloucestershire to collect the cake next week, as he wanted to ensure it remained in good condition.

He described himself as a “royal fan”, having visited Buckingham Palace on many occasions and recently went to see the statue of Princess Diana in the Sunken Garden at Kensington Palace.

Once a member of 1960s pop band The Outer Limits, he said was pleased to have won the cake at auction.

“I would have regretted losing it because it will go to really good causes now,” Mr Layton added.

Speaking after the sale, auctioneer and royal memorabilia specialist Chris Albury, of Dominic Winter Auctioneers, said: “We were amazed at the numbers of people wanting to bid on this large and unique piece of royal cake icing.

“It seemed to get far more attention than when we sold it with a Charles & Diana thank-you letter 13 years ago.

“There were lots of inquiries from bidders, mostly in the UK, USA and several countries in the Middle East.

“The bidding started at £300 and with commission bids, the internet and phone bidding, quickly rose to the winning price of £1,850.”

Mrs Smith began her career at Clarence House in the kitchen before moving on to more general duties on the recommendation of Lady Jean Rankin.

Prince Charles married Lady Diana Spencer in St Paul’s Cathedral on July 29 1981.

In addition to their main official five-tier wedding cake, some 22 other wedding cakes were supplied by various manufacturers.

Mr Albury said he believed the slice auctioned is likely to have come from either the side of a cake, or from the top of a single-tier cake.

The cake was sold on Wednesday along with printed ceremonial and order of service programmes for the wedding, and a memorial Royal Wedding Breakfast programme for Buckingham Palace.

Charles and Diana’s marriage was not to last and they split 11 years later in 1992, and divorced in 1996.

She went on to champion the disadvantaged but died in a Paris car crash in 1997, a year after the divorce, when sons William and Harry were aged 15 and 12.