Now, the SNP has called for the same kind of transparency from across the government, and has apparently set its sights on the chancellor George Osborne in particular.
Angus Robertson, Westminster leader of the Scottish party, speaking on Sky News show Murnaghan, has said: "We have heard absolutely nothing about other members of the cabinet. Where is the chancellor of the exchequer George Osborne? Has he made a declaration that he has never ever benefited from offshore trusts? What about other Treasury ministers? Have they ever benefited from offshore trusts?"
"I think the publishing of the tax returns by the Prime Minister is welcome, but it doesn't answer these wider questions and it is something that this week they are not going to get away from. If the Prime Minister doesn't make a statement to Parliament tomorrow the SNP is going to apply for an urgent question so he is brought before Parliament to update MPs of what he has done, what his cabinet have done and what his government intends to do in the future."
Labour leader Jeremy Corbyn has echoed the calls for transparency, telling the BBC he is in favour of all MPs, not just cabinet ministers, publishing their tax returns - and political journalists too.
“Money and politics have to be treated with the greatest sense of openness possible. I think we are moving in that direction, I think it’s probably a good thing if we move generally in that direction so everybody knows what influences are at play. I think we need to consider how far it goes, how far it goes to other people involved in public life,” he said speaking on The Andrew Marr Show.
“I mean you are involved in public life as a very important commentator on the BBC, as many others are," he said to Marr. "I think we need to know what influences are at work.”
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