A 40-year-old slice of Prince Charles and Princess Diana’s wedding cake is going on sale. All this while, the slice has been wrapped up and kept inside an old floral cake tin.

According to a report by The Independent, the cake slice measures eight inches by seven inches. It also features a detailed Royal coat of arms decoration, in red, gold and blue, on the icing and marzipan.

After the 1981 grand royal wedding, the slice was given to Moyra Smith, who was an employee of Queen Mother at Clarence House. It is believed to have been cut from a cake that was distributed to the staff at Clarence House. For the royal wedding, a total of 23 cakes were baked. This also included a five-foot-tall centrepiece fruitcake.

The cake tin Smith kept the slice in had a handmade label on the lid that read, “Handle with Care – Prince Charles & Princess Diane’s [sic] Wedding Cake.

Smith kept the slice till 2008, after which a collector took it and is now selling with auctioneers Dominic Winter in Cirencester, Gloucestershire.

Chris Albury, a specialist valuer at Dominic Winter, was quoted as saying, “I still wouldn’t recommend eating it but after 40 years it’s clearly destined to last. “It’s a curious and unique keepsake celebrating a royal wedding that holds an enduring fascination with British royalty aficionados worldwide.