Going through the photographs I came across one that is dated 9th June 1951. According to the caption it was taken at a ballet performance of "Tiresias" at Covent Garden.
The Queen Mother (or, in fact Queen Consort as she was at that time) is seen wearing a tiara that I cannot say that I have seen before. It looks like consisting of diamonds and coloured gem stones, though I am not sure what colour they would be.
Would anybody recognise the tiara and enlighten me, please?