Barnes & Noble (B&N) has won a small victory in its legal battle against arch-rival Amazon, which accused it of copying a shopping feature on its website.

A US court of appeals yesterday overturned a preliminary injunction prohibiting B&N from using Amazon's patented 1-Click, which enables consumers to shop without going through multiple steps or re-entering their shipping and billing information each time they buy.

The case has been not been without controversy. Soon after Amazon sued B&N for alleged patent infringement, thousands of software developers threatened to boycott the online retailer because they did not believe the invention was anything new and that a patent should not have been awarded.

In response, Amazon chief executive, Jeff Bezos, vowed to lead an effort to try to revamp patent issuing policy in the US.

But after yesterday's ruling, B&N officials claimed that the court "raised substantial questions as to the validity" of the 1-Click patent. In a statement, company bosses said: "We have said throughout this case that we do not intend to sit back and allow Amazon to stake a claim upon any technology that is widely used."

In its statement, Amazon said it remained confident that the patent is valid and that the appellate court "also confirmed Amazon's strong showing that B&N infringed the patent".

1-Click was introduced onto Amazon's site in September 1997, while B&N's Express Lane was launched in May 1998.

The case is scheduled to return to trial on 10 September.