The London Stock Exchange has warned that the European Union’s plans for a no-deal Brexit threaten investment companies’ ability to secure the most favourable prices on stock trades for pension funds and other clients.

The LSE’s concerns come after the European Securities and Markets Authority, the regulator, said EU-based investors will be forced to trade some of the biggest London-listed stocks — including BP, Royal Dutch Shell and Vodafone — within the bloc in the event the UK leaves the European Union without a deal.