Bill Gates
Bill Gates is a billionaire computer software magnate who runs a charitable foundation with his wife Melinda Reuters

Bill Gates has sold off some of his shares in controversial British security giant G4S after the billionaire computer software magnate was criticised for his investment.

The G4S shares were bought in June 2013 through the philanthropic organisation he runs with his wife, the Bill and Melinda Gates Foundation.

The investment was in more than 3% of company. But a filing at the London Stock Exchange on 28 May, 2014, shows that this has now been brought down to below 3%.

Gates is under fire from campaigners over G4S's work in the Israeli prison system.

It provides security systems to some of Israel's prisons under a contract signed with the Middle East state's government in 2007.

Campaign group War on Want argues that G4S is complicit in Israel's taking of political prisoners.

They claim that the transfer of prisoners from occupied Palestinian territories to prisons elsewhere in Israel is in breach of Article 76 of the Fourth Geneva Convention.

And Israel is accused of holding children in its prisons as well as torturing incarcerated Palestinians, both of which would also breach international law.

For these reasons Gates was attacked for his charitable foundation's investments in G4S.

But G4S boss Ashley Almanza denied his firm is in breach of international law at an annual shareholder meeting.

"We believe this contract has not breached international law and we will continue to keep these matters under review," he said.

"If we were making five times as much money in Israel, our judgment wouldn't be any different."