Conservative London mayoral candidate Zac Goldsmith has said he will publish his tax return after facing a grilling over his tax status.
"I think all candidates should in this election. If this is something the candidates agree to do then I will of course do that. I fully anticipate doing that," he told BBC Newsnight on Tuesday evening.
In response, a spokesperson for Labour candidate Sadiq Khan told The Huffington Post UK that Khan would also publish his tax return.
Last night, Newsnight presenter Evan Davis asked Goldsmith whether his own tax affairs compromised his ability to speak out against the activities of multi-nationals, such as Google, which have been accused of tax avoidance.
Until 2010, Goldsmith, a millionaire, held a non-dom tax status which he inherited from his father, Sir James Goldsmith. People with the status must pay tax on their UK earnings, but do not have to pay tax on any foreign income.
The peculiarly British status is seen as the preserve of the rich - as it comes with a price in the form of an annual payment to the Treasury.
"I have always been tax resident in the UK," Goldsmith told Davis. "I have always paid full tax on my income in the UK since I've been paying tax since I was 18."
"Let me just explain, my father died around 20 years ago. I became non-dom at age 20 or 21. Being non-dom allows you to make lifestyle choices to avoid paying tax." He added: "I've never been accused of not paying tax."
During the interview, Davis pressed the Tory MP on why his family's office was in Geneva when he was running to be mayor of London - a city with a healthy financial services sector.
"I have a huge family that covers every continent in the world, more or less. I am one of very many siblings and members of the family. My father was an international businessman. He established an overseas trust before he died," Goldsmith said.
"I am a beneficiary of that trust. I have absolutely no control over it.
Goldsmith added: "What I do have control over is the income I get. And that income I get is subject to the full tax regime in the UK and has always has been."
Asked whether he would publish his tax return in the course of his mayoral campaign battle against Labour's Sadiq Khan, he said: "Of course I will."
"I think all candidates should in this election. If this is something the candidates agree to do then I will of course do that. I fully anticipate doing that," he said.
Labour MP Neil Coyle told The Huffington Post UK: "Zac Goldsmith needs to come clean about his non-dom status and the offshore trust which he holds wealth and property in.
"It's not enough just to say he pays UK tax - that's the minimum anyone expects of a candidate for Mayor. Londoners will want to be assured that the Conservative candidate for Mayor is not using any loopholes to gain an unfair advantage.
He added: "Most Londoners are happy to buy their home without the aid of offshore trusts. Why does Zac Goldsmith have to use one?"