The famous Spencer Tiara, worn by Diana, Princess of Wales on her wedding day, is to go on display as part of the UK’s largest exhibition of tiaras in 20 years.

Some 50 glittering treasures of aristocratic and royal provenance, many seen for the first time in public in decades, will be on view as part of Sotheby’s’ Platinum Jubilee celebrations.

Diana’s brother Earl Spencer has loaned the priceless family heirloom to the auction house – the first time the piece will have been exhibited in London since the 1960s.

Lady Diana Spencer wore the elaborate garland tiara – which has a central heart-shaped motif set with diamonds flanked by continuous running scrolls, interspersed with star and trumpet-shaped flowers – when she married the Prince of Wales in a fairytale ceremony in 1981.

Lord Spencer later recalled how the sparkling jewellery gave Diana a splitting headache on the day of her nuptials because she was not used to wearing it.

The princess wore the historic tiara on many occasions afterwards, including at state dinners on royal overseas tours.

Elements of the piece are said to date back to 1767, before it was transformed into its current form by crown jeweller Garrard in the 1930s.

The heart-shaped section was said to be particularly sentimental to Diana, with her grandmother Lady Cynthia Hamilton receiving it as a wedding present from her husband Jack, later the 7th Earl Spencer, in 1919.

Kristian Spofforth, head of jewellery at Sotheby’s London, said: “The Queen’s Jubilee celebrations have given us the perfect opportunity to put on public display an outstanding selection of tiaras from noble and royal provenance, many of which have not been exhibited in decades.

“The sourcing of these jewels has been a labour of love, resulting in an exhibition that showcases the best iterations within the tiara style register, through some of its most famous incarnations – including the much-loved and photographed Spencer Tiara.

“This is also a wonderful moment for us to shine a special light on the dazzling craftsmanship delivered by generations of mainly British-based jewellers across several centuries of tiara making.”

Among the items on show will include an emerald and diamond tiara designed by Prince Albert in his favoured Gothic Revival style for his wife Queen Victoria in 1845.

It was reportedly Victoria’s favourite and is widely seen as one of the most elegant and sumptuous coloured gemstone tiaras ever created anywhere in the world.

Set in gold, cushion-shaped diamonds are interspersed with step-cut emeralds lined across its base, topped by further diamonds and emeralds shaped in scrolls and surmounted by a graduated row of 19 inverted cabochon pear-shaped emeralds, the largest of which weighs 15 carats.

Others tiaras include Josephine Bonaparte’s Gold, Cameo and Enamel Diadem, which takes inspiration from the head ornaments of ancient Greece and Rome.

It is adorned with five oval hardstone cameos made of layered agate and jasper including the head of Medusa and a profile of Zeus.

Tiaras which were worn for the Queen’s coronation in 1953 will feature including the Derby Tiara initially created for the Duchess of Devonshire in 1893, and the Westminster Halo Tiara, commissioned to Paris-based jewellers Lacloche Freres in 1930 by the Duke of Westminster for his bride Loelia Ponsonby.

Artworks depicting the queens who have ruled throughout history will also feature at the Jubilee Arts Festival at Sotheby’s, ranging from Andy Warhol’s pop art print of the Queen to the famous Armada portrait of Elizabeth I.

The event at Sotheby’s, 34-35 New Bond Street in London, will run from May 28 to June 15 – entry is free and tickets can be booked in advance.