A major traded union in the UK, Amicus, to discuss a possible merger with another union based in the US and Canada. If it succeeds, the merged union would bring 1.2 million members to Amicus'' 1.8 million, creating one of the largest unions in the world with a membership exceeding more than 3 million members.

This is the first time that an international merger between trade unions has been mooted. Amicus General Secretary Derek Simpson is due to meet officials from United Steel Workers in about a fortnight.

Previously, Simpson has spoken of creating "a single global trade union movement capable of challenging the might of multinationals". Amicus is already set to expand next month when it merges with the Transport and General Workers Union (T&G), making it the country''s biggest union.

Observers say that this was a reflection of the changing world, where union influence was in decline despite the need to represent workers in global scale companies. Although there are different labour laws in other countries, a trans-Atlantic union could put pressure on companies and their managers.