The High Court has ordered the MTR Corporation to preserve CCTV footage from Prince Edward and Lai Chi Kok stations on the night of August 31 – when police arrested dozens of suspected protesters.

Judge Anderson Chow said the recordings must be kept secure until a court rules on whether they must be handed over to a student union leader who was arrested that night and who has indicated he intends to sue the police.

While MTR bosses had already announced that they would keep hold of the footage from Prince Edward Station for three years, the judge noted that there was no such pledge for the recordings from Lai Chi Kok and there was a risk this footage could be erased or disposed of without the court order.

The case was brought by Kex Leung, head of Education University's student union, who alleges his arrest at Prince Edward was unlawful.

The station was shut down after police moved in on suspected protesters there on August 31, and media footage showed officers severely beating people inside a train.

But reporters were later sent away from the station as police dealt with around 50 people they had arrested.

Several injured people were later moved to Lai Chi Kok MTR Station by a specially arranged train before they were taken to hospital by ambulance.

Police had delayed the Fire Services Department from attending to those injured, and the fact that the initial casualty numbers were revised down from 10 to 7, sparked rumours that three people could have been killed.