David Cameron must "lead by example" and "set the record straight" on his own tax affairs, Labour has demanded the following the Panama Papers leak.
Downing Street has refused to disclose whether the Cameron family still has funds in offshore investments after claims emerged about the tax arrangements of the Prime Minister's late father, Ian Cameron, insisting it is a "private matter".
The leaked documents also include details about the tax affairs of Conservative donors, according to the Guardian, which has seen the records.
Shadow chancellor John McDonnell said: "The Prime Minister should lead by example and come out and set the record straight on his own tax affairs - we need full and total transparency.
"We also need to know the truth behind reports that the Conservative Party has received substantial donations from those linked to this scandal. The Tories should come clean and set out exactly what the situation is - is the Prime Minister happy to receive money from big donors who are accused of tax avoidance?
"Because it is those taxpayers who pay their fair share in taxes who have to shoulder the burden for those who do not. This is a basic principle that any party of government cannot take lightly."
Mr Cameron's father ran an offshore fund which avoided ever having to pay tax in Britain by hiring a small army of Bahamas residents - including a part-time bishop - to sign its paperwork, according to the Guardian.
Ian Cameron, who died in 2010, was a director of Blairmore Holdings Inc, which, until 2006, used unregistered "bearer shares" to protects its clients' privacy.
His use of the firm to help shield investments from UK tax helped build up a significant legacy, part of which was inherited by the Prime Minister.
There is no suggestion that this avoidance arrangement or others exposed by the leak were anything but entirely legal or that Mr Cameron's family did not pay the UK tax due on any repatriated assets.