An affiliate of Lloyds of London is offering a €1 million reward for information leading to a diamond collection stolen at gunpoint from a jewel show in Cannes.

The gems belonging to the Israeli billionaire Lev Leviev were on display at the hotel featured in Alfred Hitchcock’s To Catch A Thief when a gunman walked into the ground floor show, threatened a handful of unarmed guards, then disappeared down a side street with the £88.5 million cache, police have said.

The gems were supposed to be on public display until the end of August. It was not clear how many pieces were stolen. Mr Leviev said at the time: “Company officials are co-operating with local authorities investigating the loss and are relieved that no one was injured in the robbery.”

The July 28 theft at the Carlton Intercontinental Hotel, on the exclusive Promenade de la Croisette, ranks among the largest jewel heists in history.

On February 18 in Belgium, €37 million of diamonds were stolen. Robbers targeted stones from the global diamond centre of Antwerp that had been loaded on a plane headed to Zurich.

Authorities have since detained dozens of people and recovered many of the stolen items.

In December 2008, armed robbers wearing women’s wigs and clothing made off with diamond rings, bracelets and other jewellery said then to be worth €80 million from a Harry Winston boutique in Paris.

In February 2008, in a scene reminiscent of the movie The Italian Job, masked thieves drilled a tunnel into a Damiani jewellery company showroom in Milan, Italy. They tied up staff with plastic cable and sticky tape, then stole gold, diamonds and rubies worth over €15 million. The robbers had been digging for several weeks from a building being built next door.