HSBC (HSBA.L), Europe's biggest bank, is weighing plans to spin off its British retail bank in a 20 billion-pound ($30.37 billion) deal, the Sunday Times reported.

Directors at the bank are considering the future of its UK retail operations, the newspaper reported, citing senior sources.

HSBC declined to comment on the report.

HSBC has ordered a review into whether it should move its headquarters out of Britain and potentially back to its former home in Hong Kong, threatening London's reputation as a global hub for finance and investment.

A UK law forcing banks to separate their domestic retail operations by 2019 is likely to be a key factor in any decision. If the bank does move, it could choose to spin off its UK arm, investors have said.

Founded 150 years ago as the Hongkong and Shanghai Banking Corporation, HSBC issues most of Hong Kong's bank notes and has made $24 billion in profit there over the past three years, compared with a $4 billion loss in Britain over the same period.