Allen & Overy (A&O) is advising Nomura on the transfer of client business from London to Germany, as the Japanese banking giant prepares for the implications of a possible hard Brexit.

The bank has contacted its EU-based clients to inform them of plans to transfer business to its newly launched Frankfurt hub to guard against potential disruption when the UK leaves the EU in March next year.

In a letter from Nomura to its clients, obtained by the Press Association, the bank 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."

The bank was granted a licence by German regulators for its new post-Brexit Frankfurt base earlier this year, at which point it stated: "Nomura's plans are well advanced and the licence is a major step towards ensuring that all current client and counterparty relationships, and access to Nomura products and services, will continue without disruption after the UK leaves the EU."

A&O is a longstanding adviser to Nomura, winning a spot on its legal panel in 2016. The firm also advised the bank on its move into new premises in the City in 2009, with real estate partner Adam Cleal leading A&O's team.

A&O was contacted for comment.