London has been crowned as the world's top city of opportunity for the second year in a row but faces major "challenges" from the Brexit vote, according to a report.
PwC's latest Cities of Opportunity Index revealed London scored top marks once again thanks to its economic importance, reputation as a city gateway, ease of doing business, innovation and culture.
The report - which was compiled before the EU referendum - also found it significantly extended its lead in the index, with a 6.5% advantage over its closest rival Singapore, followed by Toronto, Paris and Amsterdam.
London kept the top spot for economic clout, beating fellow global powerhouses New York and Beijing.
But it was found to be the most expensive city for cost of living and business occupancy, losing out to Johannesburg, Toronto and Los Angeles which were the three most affordable cities.
Experts at PwC also warned there were risks Brexit could impact the capital, possibly hitting recruitment, trade and regulation, although they said it was too early to gauge the effect.
Mayor of London Sadiq Khan welcomed the report and brushed aside Brexit concerns.
He said: " This is the best city in the world; it's open for business, creative, entrepreneurial, agile, full of opportunity and a hub for business and leisure travel.
"Despite the recent vote to leave the European Union, there is no doubt that this will continue to be the best place in the world to do business."
PwC said London scored highly across its range of 10 indicators measuring the performance of 30 major global cities, such as economic importance, reputation as a city gateway, ease of doing business, technology, transport and innovation.
But PwC partner David Snell said: "Change is ahead and it remains to be seen what impact the UK's decision to leave the EU will have on our vibrant city."
He said the Brexit negotiations would offer a " major opportunity for financial services firms to work with regulators, investors and clients in order to shape a new rulebook fit for the new climate".
Across the performance indicators, London ranked within the top three for economic importance, ease of doing business, intellectual capital and innovation, technology readiness, being a city gateway, demographics and liveability.
The index also found London performed strongly for the quality of universities and access to libraries and is one of the top cities best suited for young people aged between 15 and 29.
It likewise came top in its attractiveness to employees looking to relocate, according to PwC.