This is not the first legal clash between the two companies.

In 2014, Microsoft changed the name of its cloud storage service from SkyDrive to OneDrive after the High Court in London ruled Sky's trademark had been infringed.

However, a spokeswoman for Microsoft said it was not now facing the prospect of another imminent rebrand: "The case was not a legal challenge to Skype's use of the mark, it was only against the registration. We're confident that no confusion exists between these brands and services and will appeal. This decision does not require us to alter product names in any way.".

Microsoft believes it still has the means to prevent anyone else from trying to call their product Skype.

A further appeal is therefore likely, to the European Court of Justice itself, even if only on the basis that the Skype brand is now worldwide and must be of huge value.