Microsoft has been prohibited from selling flagship software offering Word in the US because of successful legal action taken against the company in Texas by i4i.

The prosecuting company supplies Word XML authoring software and has insisted that Microsoft has infringed its 1998 patent (number 5,787,499) which allows customers to read XML programming language in order to customise document formats.

Embedded in Microsoft Word is the capability for users to read and write XML documents.

In March 2007 i4i filed the original lawsuit and in May this year the US District Court for the Eastern District of Texas found the Redmond giant guilty of infringing the patent and fined Microsoft $200m (£122m).

Now the same court has ruled Microsoft has to stop selling Word in 60 days.

Microsoft could not be reached for comment. However, according to The Seattle PI’s Microsoft Blog, Microsoft representative Kevin Jutz said in a statement: " We believe the evidence clearly demonstrated that we do not infringe and that the i4i patent is invalid. We will appeal the verdict."

In the unlikely event that Microsoft does not manage to appeal the verdict and the decision stands, it could build a work around for the problem or remove the offending code.