The VC awarded to 21-year-old Robert Jones, of Monmouthshire, fetched just pounds 98 when it was last sold at auction in 1950. This time, experts say it could top the pounds 132,000 paid in 1992 for a First World War pilot's VC collection. Of the 11 VCs awarded after the defence of the African missionary station on 22 January 1879, all but two are in regimental collections. The other one - awarded to Lt John Chard, who commanded the defence, played in the film by Stanley Baker - is believed to have been lost.
The sale, by the specialist London auctioneers Dix and Webb of Old Bond Street, will be held on 11 June.