Prime Minister David Cameron said on 5 April, he did not own any shares or have offshore funds, after his late father, Ian Cameron, was included in a leaked list of clients using law firm Mossack Fonseca in the tax haven of Panama.

"I own no shares. I have a salary as prime minister, and I have some savings, which I get some interest from, and I have a house," he said at a question and answer session while campaigning to keep Britain in the European Union.

"I have no shares, no offshore trusts, no offshore funds, nothing like that," he said at an event in Birmingham.

Cameron's father has been reported to have run a network of offshore investment funds, and when asked on Monday to confirm that no family money was still invested in the funds, Cameron's spokeswoman said it was a "private matter".

The opposition Labour party leader Jeremy Corbyn called for an investigation into the claims made in the leaked Panama documents. "It's not a private matter if tax has not been paid, so an investigation must take place, an independent investigation, unprejudiced to decide whether tax is owed or not," he said.

Mossack Fonseca director Ramon Fonseca has denied any wrongdoing. He said the firm had suffered a hack on its database and described the leak as "an international campaign against privacy", according to Reuters.