Even, it appears, at the royal marriage of the decade.

According to Italian media reports, last weekend's wedding of Prince Felipe and Princess Letizia of Spain ended in a punch-up which left an Italian aristocrat nursing bruised lips.

Leaving a dinner given by King Juan Carlos and Queen Sofia on the evening of their son's nuptials, the heir to the Italian throne, Prince Vittorio Emanuele, was said to have hit his cousin and rival, Duke Amedeo, on the steps of the Spanish royal residence.

One report said the Duke was twice punched in the mouth and would have fallen to the ground had he not been caught by deposed Queen Anne-Marie of Greece.

The daily, La Repubblica, said Duke Amedeo was then helped inside the Zarzuela palace, where an unidentified Arab potentate applied an ice pack to his bruised lips.

On learning of the affray, King Juan Carlos was said to have stormed "Nunca más" (Never again) - apparently in reference to the Italian's chances of a further invitation.

Duke Amedeo did not deny the attack. The newspaper La Stampa quoted him as saying it was "an unpleasant business that does not deserve further comment". The incident was the latest scandal in the life of Prince Vittorio Emanuele, who returned to Italy last year after 57 years in exile.

In 1991, he was acquitted of manslaughter by a French court for an incident 13 years earlier in which he fired a rifle from his yacht off Corsica, fatally wounding a German tourist.

The prince renounced all claims to the throne as part of the deal that allowed him back into Italy - a move that dismayed the country's dwindling band of monarchists and prompted many to switch their allegiance to Duke Amedeo.