Ed Miliband will promise to end a colonial-era symbol of inequity in the tax system by announcing that, if he wins the election, he will abolish the non-domicile rule that allows many of Britain’s richest permanent residents to avoid paying tax in the UK on their worldwide income

Labour will say the rule, introduced by William Pitt the Younger in the late 18th century, has been wide open to abuse and offends the moral basis of taxation. Everyone who has made the UK their permanent home should pay full UK tax on all their income and gains, he will argue

In a speech in Warwick on Wednesday, Miliband is expected to say the non-dom rule, believed to be used by more than 110,000 wealthy people in a system unique to the UK, is born of a discredited belief that “anything goes for those at the top and that what is good for the rich is always good for Britain”.

Non-doms pay UK income tax and capital gains tax on their UK sources of income and gains, and whatever income generated overseas they choose to remit to the UK. By contrast, UK domiciles have to pay tax on all of their income and gains, wherever in the world they are made – Britain or overseas.