LONDON (Reuters) - Banks in Britain have tried to reassure their London staff over possible Brexit disruption, including a shift in jobs to continental Europe, as Prime Minister Theresa May triggered formal EU divorce proceedings on Wednesday.

Investments banks Goldman Sachs and Nomura were among those who sent messages to employees in London, Europe's biggest financial center, as they work out how to keep serving clients across the European Union after Britain leaves the bloc.

Morgan Stanley also informed employees in Europe that no decisions had yet been made on changes for when Britain departs, leaving the EU with 27 member states.

But Rob Rooney, CEO of Morgan Stanley International, was blunter in updating them on the work of a committee comprising senior leaders at the bank which has been making Brexit contingency plans for over a year.

"As prudence would dictate, we have been preparing for a worst case scenario, in which we would need to establish a more significant entity within the EU 27," Rooney said in a memo to staff on Wednesday seen by Reuters.

"We continue to monitor the situation closely and, when appropriate, will take the necessary decisions and begin to execute on our plans."