The World Health Organisation (WHO) has voiced its concerns over the sponsorship deal between a prestigious ATP tennis tournament and Imperial, one of the largest tobacco manufacturers in the world.

The Basel ATP World Tour 500 tournament in Switzerland will be sponsored by Davidoff, Imperial's luxury brand of goods which include cigars and cigarettes.

Tobacco advertising has been banned by the EU in all its member states since 2005, but Switzerland is not in the EU, thus the sponsorship is legal.

ATP's decision to accept Imperial as a sponsor has attracted criticism from WHO and a number of European campaign groups, such as the UK's Action on Smoking and Health (Ash).

The satellite broadcaster Eurosport has dropped plans to show the event after French anti-tobacco campaigners threatened legal action.