The 329-year-old group said it had recently updated guidance to its 800 employees drinking alcohol during the day, bringing it into line with financial service industry peers, many of which have already looked to curtail boozy meetings.

“It provides clarification on the rules around alcohol consumption, which is prohibited during business hours. The guidance removes any ambiguity on the policy,” a Lloyd’s spokesman said in a statement.

The guidance is intended to reflect common and business standards and “ensures we are in line with a number of businesses in the sector who also adopt similar policies”, he added. It does not affect brokers and underwriters who work at Lloyd’s for other firms.

The move will be a blow to publicans at the hundreds of drinking establishments in London’s financial district, as the industry reels from thousands of job cuts at banks and the impact of Britain’s vote to leave the European Union.

Lloyd’s itself is expected to move some operations out of its iconic, Richard Rogers-designed headquarters in London to a new subsidiary in the EU, with Dublin, Paris and Luxembourg all mooted as possible locations.

(Reporting by Simon Jessop; Editing by Rachel Armstrong)