The defence team has challenged the authenticity of news footage submitted at the trial of seven police officers accused of beating Civic Party member Ken Tsang Kin-chiu during the 2014 pro-democracy Occupy protests.

The prosecutors attempted to submit four news clips, from TVB, ATV, Now TV and Apple Daily, as evidence in court, but the defence lawyers objected. They said the prosecution has not been able to prove the process of recording, the source of the footage and that the footage had not been tampered with, Stand News reported.

Defendants in the Ken Tsang assault case. Photo: Stand News.

Tsang was filmed allegedly being kicked and punched by seven police officers near government headquarters in Tamar, Admiralty during the Umbrella Movement demonstrations.

Deputy Director of Public Prosecutions David Leung Cheuk-yin said the ATV and Now TV footage showed how Tsang had been arrested, while the TVB clip showed Tsang being escorted by the police and allegedly assaulted.

The prosecution said they would bring in three witnesses from TVB, including technical staff who monitored the news footage and burned the clip on to a blu-ray disc.

Ken Tsang. File Photo: Apple Daily.

The trial began on Wednesday at the District Court. All seven were charged with wounding and striking with intent to do grievous bodily harm, while one was charged with an extra count of common assault. The police officers all pleaded not guilty.

The trial is expected to take 20 days. The case was adjourned until Friday.