LONDON: Financial markets will be disrupted in January unless the European Union allows the bloc's investors to use derivatives trading platforms in London, a group of financial industry bodies have said.

"In the absence of action from policymakers, there will be disruption in the market as of 1 January, as not all clients across the industry will be ready to put in place alternative solutions on that date, despite best efforts," said their letter to EU financial services chief Mairead McGuinness.