European financial centres will not enjoy easy pickings after Brexit should businesses decide to leave, the head of the London Stock Exchange has said.
Xavier Rolet, chief executive of the LSE Group, hailed London as unparalleled in its provision of services and raising capital, whether for projects in China, India or European small and medium-sized business.
However the next port of call for businesses seeking to leave post-Brexit would not be Paris, Frankfurt and Amsterdam, but New York, as it is the only other global financial centre that could centrally and efficiently clear all 17 major currencies, he said.
Writing in the Daily Telegraph, Mr Rolet said: "The UK financial ecosystem, with clearing at its heart, makes London the most economically attractive and stable destination for global investors and issuers.
"It is no longer just a few banks transacting individual products but the innovative home of global finance."
Leaving the UK could cost firms tens of billions of dollars and that would also take money from the European real economy, warned the Frenchman who was appointed head of the exchange in 2009.
Mr Rolet called for entrepreneurs to be "at the centre" of the post-Brexit industrial strategy.
He said: "This ecosystem must be championed and protected. The best way is to secure continued regulatory equivalence with the EU, membership of which also provides equivalency with the US.
"But people in Europe and the UK should realise this isn't a zero sum game. If business leaves the UK, the European economy would suffer - and very little of that business is likely to go to Europe anyway."