LONDON (Bloomberg) — British banks received a net $257 billion from operations in the nation's offshore tax havens as of June 30, according to a government report.

The funds are mainly bank deposits collected in offshore centres such as Jersey and the Isle of Man that are "upstreamed" to mainland headquarters, according to a report published yesterday.

"The offshore financial centres are certainly assisting the City of London because they provide more funds for the banks to on-lend," said Michael Foot, the former Bank of England official who led the review of nine offshore centres.