Despite hopes for a good free trade deal with Japan, the United Kingdom is unlikely to improve on the recent agreement between Tokyo and Brussels, and could end up worse off, experts say.

They argue the U.K., on its own, could lose negotiating leverage with Japan and fail to further open up the country's services sector to U.K. firms — an area the government is keen to focus on in deals with advanced economies like Japan.

Foreign Secretary Boris Johnson hopes the U.K. can better the free trade agreement recently struck between Japan and the European Union, which will eliminate tariffs and lower regulatory barriers.