The exchange was investigating a "potential trading services issue" and would have further information by 0750 GMT, it said in a statement on its website.

An LSE spokeswoman said a "technical issue had affected trading in some securities," but she had no further detail on the cause of the fault or when the problem might be resolved.

In June 2018, trading on the LSE, one of the world's largest stock markets, was delayed by an hour due to a technical fault.

Reuters News' parent Thomson Reuters  holds a 45pc stake in Refinitiv, which is being bought out by the LSE. Thomson Reuters will own 15pc in LSE after the proposed deal closes.