A Hong Kong bookseller and British passport holder who disappeared last year has said he will renounce his British citizenship, adding that he had not been kidnapped by Chinese authorities as suspected, but had snuck into China illegally.

Lee Bo, a dual British and Hong Kong citizen, and four associates had gone missing over the past half-year, sparking fears that Chinese authorities had abducted some of the men and taken them back to China.

The disappearances provoked concern that China was using shadowy tactics to erode the "one country, two systems" formula under which Hong Kong has been governed since its return to China from British rule in 1997.