Xavier Rolet, chief executive of the London Stock Exchange, reckons Britain will build a fintech firm worth £100bn in the next decade.
Talking at the Conservative party conference, Rolet said the UK had a competitive advantage in fintech because the finance and technology experts fuelling the industry all work closely together.
The United States, by comparison, will struggle to build such a thriving fintech sector because its technology gurus are on the west coast, and the finance firms are in the east, he said.
He said it would be "conservative" to expect a fintech firm valued at between £100bn and £300bn to come out of London in 10 years.
The second sector to keep an eye on in Britain was life science, Rolet said, because the UK excels in research and development.