Michael Bloomberg, New York’s mayor, has given his strongest hint that he may seek to run for US president as a self-financed independent candidate by filing papers to drop his affiliation with the Republican party.

Mr Bloomberg, a lifelong Democrat who switched parties before running for mayor in 2001, has repeatedly shot down suggestions that he will run for president next year. But his actions in recent months have encouraged the speculation – particularly his frequent trips outside of New York, which have given the appearance of a politician seeking to raise his profile nationally.