ZAC GOLDSMITH is the target of a new tax-justice campaign launched yesterday to push him to “come clean” about his non-dom past.

The Tory mayoral candidate only registered in Britain for tax purposes when he first stood for Parliament six years ago, previously hiding his fortune abroad.

Now the Where’s Zac’s Tax? campaign and website, launched by the Transport Salaried Staffs Association, is seeking to establish how much tax he paid before he was elected.

Mr Goldsmith has picked up more than £6 million in taxable income since 2010, the vast majority of it from a family trust set up by billionaire dad Sir James Goldsmith, who founded and bankrolled the Referendum Party.

The Richmond Park MP has made a further £4.3m in profits from selling assets.

Launching the campaign, TSSA general secretary Manuel Cortes said: “The Panama Papers have shown the creative lengths the rich go to to avoid paying tax and ordinary folk are sick to the back teeth of it.

Mr Goldsmith’s average annual income over the last five years was £1.2m — 36 times the median salary for full-time workers in the capital. This puts him in the highest-earning 0.05 per cent of British taxpayers.

“Zac’s shown not he’s not in it together with Londoners — but he’s right up to his neck in it as a dodgy threesome with his Eton playmates Dodgy Dave and Dodgy George,” Mr Cortes said.