Italy’s uneasy relationship with its royal past has been cast into the spotlight by the imminent auction of jewellery by the daughter of the country’s last king.

Princess Maria Gabriella of Savoy, 67, the daughter of Umberto II and Queen Marie José, is selling 41 of her “rare and stupendous” jewels at Christie’s in London next week. The princess says that she needs to raise money to settle a tax bill.

The centrepiece is a diamond tiara, which she inherited from her mother, made by Fabergé in 1895. The tiara is estimated to be worth between €580,000 (£390,000) and €880,000, but experts said that it could fetch up to three times that sum.

It is known as the Empress Joséphine Tiara because it contains pear-shaped or tear-drop diamonds given by Tsar Alexander I to the Empress Joséphine after her divorce from Napoléon I.

The auction has raised much interest in Italy, reviving debate over the fate of the main collection of royal jewels, which have lain in a Bank of Italy vault in Rome since 1946 and have not gone on public display. The decision to keep the Savoy Treasures under lock and key is the result of continued uncertainty over the ownership of the jewels.

They include a double string of diamonds containing 1,859 stones, a ten-string pearl necklace with 684 pearls given by King Umberto I to his consort Queen Margherita and a pink diamond that once belonged to a Sicilian ally of Napoléon. Italy’s ambivalent attitude to the monarchy stems from the reign of King Victor Emmanuel III who was regarded by many as complicit with the dictatorship of Benito Mussolini. The former Royal Family lost much of its fortune and forfeited all claims to royal palaces and estates after the end of the monarchy in a closely fought referendum in 1946. Although every Italian town has a square or street named after King Victor Emmanuel II, who unified Italy in 1870, attitudes to the former monarchy have been, at best, ambivalent since the Second World War. Prince Victor Emmanuel, 70, Maria Gabriella’s brother and heir to the defunct throne, became a banker and helicopter salesman in exile in Switzerland until his return to Italy in 2003, when a ban on male members of the House of Savoy entering the country was lifted. He officially renounced the family’s claim to the crown jewels after returning to Italy.

The reputation of the former Royal Family has not been helped by recent scandals involving surviving members. Prince Victor Emmanuel’s reputation never recovered after he was accused of killing Dirk Hamer, a German tourist, on a boat in Corsica in 1978, even though he was later cleared by a French court. He is infamous for his gaffes. At one stage he apologised for suggesting that Mussolini’s treatment of the Jews was “not so bad”.

More recently Victor Emmanuel became embroiled in scandals and corruption allegations, culminating in his arrest last year on charges of involvement in a gambling and prostitution ring. He has since been released, and charges have not been pressed. But the episode led to an estrangement with Maria Gabriella, who said that she no longer considered her brother a royal and that the “true head” of the dynasty was their cousin Amedeo, Duke of Aosta.

When the Queen visited Italy in 2000, some Italian officials said that the jewels were the property of the Italian nation and should be put on public display. Last year Mario Draghi, the governor of the Bank of Italy, said that he saw “no reason why the jewels should not see the light of day”, suggesting they could be displayed either Rome or in Turin.

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