Mr Gates became a victim of Belgium's notorious "entarteurs" or pie throwers on a visit to the country last February.

Gerrit Zalm: Under fire from euro-protesters

As the world's richest man attended a reception in Brussels, he was hit by four fresh cream tarts.

Pictures of the computer magnate with fresh cream spattered over his face and suit were beamed around the world.

His attackers Brian Keegan and Remy Belvaux were fined after being found guilty of "mild violence".

It is the first time any of the pie-throwers, who call themselves ''pastry terrorists'', have been convicted.

The group's mastermind, Noel Godin, has vowed to "assassinate through ridicule all world celebrities who take themselves spectacularly seriously".

He says Mr Gates was "only injured in his self-esteem".

'We want Clinton and the Pope'

Previous targets have included actress Catherine Deneuve, desiger Karl Lagerfeld, singer Kenny Rogers, avant-garde film director Jean-Luc Godard and philosopher Bernard-Henri Levy.

And the practice seems to be spreading. On Monday Dutch Finance Minister Gerrit Zalm received two custard pies in the face as he launched trading in the euro.

On their Website, entitled ''gloupgloup'', the pastry terrorists threaten to pie Mr Gates again in the next few months.

They are also after US President Bill Clinton, British Prime Minister Tony Blair, the Pope and actress Demi Moore for her film GI Jane.