The tax, designed as a top-up to income tax, aims to address the growing wealth inequality by ensuring billionaires pay at least 2% of their wealth in taxes.

French economist Gabriel Zucman, who authored the report, argues that advancements in taxing multinational corporations have paved the way for this global levy on individuals, even without universal participation. The plan involves valuing billionaires’ wealth, mainly held in shares, and implementing measures like stricter exit taxes and a “tax collector of last resort” mechanism.

The proposal, backed by organisations like Oxfam and Patriotic Millionaires UK, will be discussed at the upcoming G20 meeting. It is seen as a crucial step towards tackling the extreme concentration of wealth and ensuring a fairer tax system.

Oxfam International’s interim executive director Amitabh Behar said: “We welcome the Zucman report, which offers a critical contribution toward fixing a system that allows the ultra-rich to avoid taxes and not only accumulate and protect astronomical amounts of wealth and income - but also hide it from governments.

“That governments are taking taxing the ultra-rich seriously shows national politics are finally catching up with public disgust at the super-rich having wriggled out of paying their fair share of tax for far too long. The Zucman report mirrors what so many ordinary people - and even millionaires - are pushing for.

“Any global deal to tax the super-rich needs to be substantial and ambitious enough to bring down inequality. For example, an annual net wealth tax of more than 8 per cent would be needed to reduce billionaire wealth.

“Taxing the ultra-rich properly could raise billions of dollars for governments to combat inequality and tackle the climate crisis. Every government needs to act nationally, yes —but they also need to cooperate internationally given how effectively the ultra-rich can evade across borders.

“Zucman’s report sends a clear memo to the ultra-rich – ‘your wealth and power can’t shield you from paying your fair share any longer’. It could be a significant step forward in mending our broken, divided and unequal societies.”