Cameron himself has come in for personal criticism as his family benefited greatly from his late father's firm, which ran an offshore fund and never paid any UK tax. Thus, Cameron was able to be educated privately and go to Oxford.
Cameron has talked tough on aggressive tax avoidance, putting the matter on the agenda at the World Economic Forum in Davos in January 2013. He said: "We want to use the G8 to drive a more serious debate on tax evasion and tax avoidance. This is an issue whose time has come. After years of abuse people across the planet are rightly calling for more action, and most importantly there is gathering political will to actually do something about it.
How to fill out your next tax return until PM David #Cameron answers questions over #panamapapers revelations… pic.twitter.com/6aW9On31uA
— Sara Firth (@Sara__Firth) April 5, 2016
"There are some forms of avoidance that have become so aggressive that I think it is right to say these raise ethical issues, and it is time to call for more responsibility and for governments to act accordingly," Cameron said.
Later that year, he put it on the agenda at the G20 summit in St Petersburg. Speaking after the meeting, Chancellor George Osborne said: "Earlier this year the UK government put a fairer tax system at the heart of the agenda when David Cameron chaired the G8 summit. This week's agreement shows the G20 leaders adopting this agenda and making it their own and that is a huge milestone on the road to making the international tax rules fairer."
"That's a private matter" No 10 when asked if Cameron's family still has money in Panama tax haven #PanamaLeaks pic.twitter.com/C9L141ylyB
— Ali (@The45Storm) April 4, 2016
'Rotten System'
However, since 2013, Cameron has done little to tackle the tax affairs of the many British Overseas Territories, including the British Virgin Islands, Bermuda and the Cayman Island — all of which feature prominently in the Panama files.
"This leak exposes the extent to which UK tax havens and UK-based intermediaries are at the very heart of this rotten system. The Prime Minister has the power to clean up a major chunk of the global financial system, and in the light of the Panama Papers, he should use it," said Toby Quantrill, Christian Aid's Principal Economic Justice Adviser.
Dear Downing Street the Cameron family tax dealings are NOT a "private matter" while millions being hurt by austerity.#PanamaLeaks
— Will Black (@WillBlackWriter) April 4, 2016
"[The British Virgin Islands] is a British colonial independent territory. Surely to goodness we can at least stop tax evasion and avoidance in British controlled territories. This has to be addressed…" UK Labour Party leader Jeremy Corbyn told the BBC.
"[The government should] say to the governments, those that administer the Cayman Islands, British Virgin Islands, and a number of other places, 'Hang on, you are a government of a British dependent territory, a crown territory, you must obey UK tax law, you must not become a harbor for tax avoidance and tax evasion,' " he said.