LONDON (Reuters) - Britain must be able to transition smoothly when it leaves the European Union and that will be an important part of negotiations with the bloc, finance minister Philip Hammond said on Sunday.

Hammond told ITV television that businesses in Britain would face "an unprecedented level of uncertainty" as the government negotiates its exit deal with the European Union.

"You're right of course that some visions of a future arrangement could take quite a long period of time to negotiate," he said in reply to a question about whether Britain's aim for a "bespoke" Brexit deal could take up to 10 years.

"Therefore, how we manage the transition from where we are now, out of membership of the European Union into a new long-term relationship, is going to be an important part of the overall discussion."

(Reporting by Elizabeth Piper and William Schomberg; editing by Jason Neely)