The patent rights to the exterior design of Jaguar Land Rover's (JLR's) Range Rover Evoque have been annulled by China's intellectual property regulator, a development that may affect JLR's lawsuit against a domestic automaker on allegations that the latter copied the Evoque's exterior design, experts said Monday.

At the request of domestic carmaker Jiangling Holdings, which is the defendant in the suit, the patent covering the exterior design of the Range Rover Evoque sport utility vehicle (SUV) was annulled on April 6, according to information on the website of the Patent Examination Board under the State Intellectual Property Office.

Chinese media spotted the information on Monday. It is not clear when the decision to annul the patent rights was posted on the website.

Jiangling has been sued by JLR for issues "surrounding copyright and unfair competition," JLR said in a statement sent to the Global Times on June 5. Specifically, the Landwind X7 SUV produced by Jiangling has been accused of copying JLR's design.

The annulment was made on the grounds that the JLR design had already been made public before the company filed its patent application in China in November 2011. China's patent law stipulates that a design qualified for a patent should be significantly different from an existing design.

Because the design had been publicly revealed prior to the patent filing, it was considered an "existing" design.

With the annulment of JLR's patent, the company's lawsuit against Jiangling may be affected, Xu Xinming, a senior partner specializing in intellectual property rights (IPR) at Beijing Mingtai Law Firm, told the Global Times Monday.

A curious fact in the case is that the patent for the exterior design of the Landwind X7 itself was also annulled by the patent examination board on May 13 at the request of JLR, information on the board's website showed, because it was too similar to JLR's design.

The annulment of Jiangling's patent may seem straightforward, but many observers wonder how that happened when the patent the Chinese company supposedly violated had itself been voided weeks earlier.

Xu explained that under the current patent law, as long as a design generally resembles an existing design, it's difficult to obtain a separate patent. Therefore, although JLR listed some differences between the current Range Rover Evoque and the design that was made public before the application, the patent was still annulled, Xu said.

Either company can appeal the patent board's decisions with the courts within three months after receiving the decisions.

Calls to JLR went unanswered on Monday and Jiangling was not available for comment as of press time.

This is not the only case of an IPR dispute in the Chinese auto industry. In 2004, GM Daewoo Auto & Technology Co, owned by US auto giant General Motors (GM), sued domestic automaker Chery Automobile Co for alleged piracy of a small car developed by GM Daewoo. The two ultimately reached an out-of-court settlement in November 2005.

"It is inevitable for firms at their nascent stage to learn from leaders in the industry, but the bottom line is that they must act within the legal framework," Beijing-based independent auto analyst Zhang Zhiyong told the Global Times Monday.

Zhang also said that automakers in China have become increasingly aware of the importance of IPR protection.