Nomura has reportedly written to clients informing them how the bank will move their business relationship from London to Frankfurt as it prepares for a chaotic "no deal" Brexit.

Trading clients based in the EU are being asked to prepare for the move, which would allow the giant Japanese bank to continue serving clients even if current trading arrangements break down, according to the Press Association.

Financial firms in the City have warned that leaving the EU without a transitional arrangement in place by the exit date, 29 March 2019, would prevent London-based businesses from serving clients in the EU and vice versa.

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City firms currently rely on passporting arrangements to trade with the EU, meaning they do not have to establish separately regulated entities within other countries in the bloc.

A copy of the Nomura letter seen by the Press Association said: “We are ready to begin onboarding clients to this entity so that we are fully prepared in the event of a ‘Hard Brexit’ – i.e. that the UK leaves the EU on the 29 March 2019 and UK financial services organisations lose their passporting rights at that time.

“We recognise that transitional arrangements may extend this deadline but since it is not yet known how comprehensive those arrangements may be, or what services they will cover, we are making plans to ensure that our service to you can continue without disruption in any eventuality.”

Nomura announced last summer that it was setting up a subsidiary in Frankfurt to carry out trading operations, with around 100 people expected to move out of London. Nomura Financial Products Europe gained a securities trading licence from the German regulator in June this year.

The bank declined to comment.

Read more: Threat of ‘no deal’ Brexit weighs on British businesses

Full story: Nomura writes to clients on Frankfurt move in ‘no deal’ Brexit preparation: City A.M.