Sydney, Melbourne and Perth saw their millionaire populations rise by around 4,000, 3,000 and 1,000 respectively, hitting 95,400, 66,800 and 28,000 respectively. The growth followed inflows from China, Europe, the UK, the US and South Africa. Other parts of Australia such as the Gold Coast, Brisbane, Noosa and the Sunshine Coast also benefitted from inflows.

London experienced a comparatively low net inflow of around 500 millionaires in 2015 as 2,500 left the city and 3,000 came in. Many of those that left moved to other parts of England, mainly to small towns in the London commuter belt along the Thames. A large number also moved overseas, mostly to English-speaking countries such as Australia, Canada, New Zealand and the US, according to the report.

Interestingly, most of the millionaires that left London were UK-born whereas almost all of the millionaires that came into the city were from abroad.

“This may be a trend that continues in future as several wealthy UK-born people that we spoke to said they were concerned about the way London and the UK in general had changed over the past decade or so. Australia seems to be their preferred destination,” New World Wealth said.

The likely trajectory of wealthy UK citizens will no doubt become clearer following June's referendum on the country's membership of the European Union. According to NWW, a "Brexit" could strengthen alliances with former English colonies – specifically Australia, the US, Canada and New Zealand – as well as India and China, enhancing freedom of movement between the UK and these countries.

“In our view, a Brexit will not result in an outflow of millionaires from the UK. On the contrary, we believe that wealthy UK citizens are more likely to stay in the UK if there is a Brexit. This view is backed up by the fact that most of the wealthy British people we interviewed voiced concern over the UK’s open border policy with Europe,” the firm said. 

Elsewhere, the number of millionaires in Tel Aviv, Israel, grew by 2,000 to 29,000, thanks to large inflows from Europe, especially France. Meanwhile, millionaires in North Africa and Turkey moved to Dubai, pushing the city's number up by 2,000 to 42,000.

In North America, San Francisco, Seattle and Vancouver all saw large millionaire inflows from China and Southeast Asia. The cities' millionaire populations climbed a respective 2, 8 and 5 per cent to 129,000, 25,300 and 19,600.

France suffered the biggest net loss – of 10,000 millionaires – last year. This was attributed to rising religious tensions between Christians and Muslims, especially in urban areas. NWW expects millionaire outflows from France to deepen over the next decade as these tensions escalate.

China and India also recorded significant outflows – of 9,000 and 4,000 respectively – but these countries are still producing far more new millionaires than they are losing. 

New World Wealth's database of high net worth individuals comprises dossiers on over 150,000 HNWIs worldwide. Millionaires – or HNWIs – were defined as individuals with net assets of at least $1 million excluding their primary residences.