Forty years after Prince Charles and Lady Diana Spencer‘s fairytale wedding, a slice of the wedding cake is going up for auction.

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

It was given to Moyra 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 has come up for auction once again, coinciding with the 40th anniversary of Prince Charles and Lady Diana Spencer’s wedding.

Chris Albury, auctioneer and senior valuer at Dominic Winter Auctioneers in Cirencester, Gloucestershire, said: “It appears to be in exactly the same good condition as when originally sold, but we advise against eating it.”

It is expected to fetch between £300 and £500 when it goes under the hammer along with an order of service, ceremonial details and a royal wedding breakfast programme.

The wedding of Prince Charles and Lady Diana Spencer took place on Wednesday 29 July 1981 at St Paul’s Cathedral in London, United Kingdom.

Their marriage was widely billed as a “fairytale wedding” and the “wedding of the century”. It was watched by an estimated global TV audience of 750 million people.

Events were held around the Commonwealth to mark the wedding. Many street parties were held throughout the United Kingdom to celebrate the occasion. The couple separated in 1992 and divorced in 1996 after fifteen years of marriage.