The Chinese University of Hong Kong’s Willy Lam said "it seems that law and order has broken down and the normal running of government has broken down". Men in white shirts attacked commuters, media and residents in full view of security cameras and video and in many cases didn’t wear masks. A pro Beijing legislator Junius Ho posed for photographs with some of the men outside the station and said on Facebook on Monday that he knew some of the men and regarded them as "chivalrous". An expert in triad societies at the City University of Hong Kong, Professor T Wing Lo said that although legally it couldn’t be proven the men in white shirts were triads, "the fight last night was mobilised by a triad group, most probably Wo Sing Wo". Triad groups, which can’t cross into each other’s territories, are strong in the Yuen Long area of the New Territories, he said.

He said of the 200-300 men in white shirts at Yuen Long massing outside the train station and beating people it was likely "half were triad and half were villagers paid by someone". He said such village men were typically paid $HK500 ($90) a night and more if they were injured in incidents. "Beijing officially claims some triad leaders are patriotic and help maintain social order in Hong Kong... [through] United Front the CCP try to co-opt a lot of people including triad leaders. The triad leaders get a lot of money from the CCP through middle men." Graffiti defaces a sign and a wall outside the Liaison Office of the Central People's Government during a protest in the Sai Ying Pun district of Hong Kong, China. Credit:Bloomberg "If the CCP think they can't do something by themselves they use the triads to do that," he said.

"We call this extra legal governance, where triads do the dirty jobs for Beijing or police." Police commissioner Lo denied links between police and triads and said the delay in sending police was caused by a manpower problem. Hong Kong police came under fierce criticism on social media for the long delay in responding to emergency calls from the shopping mall management, the MTR station staff and Yuen Long residents who lived in the tower above the MTR station. The first attacks came around 10.45pm and police said they took 35 minutes to respond. Loading But the white-shirted men later returned. When riot police arrived around 1am they didn’t make arrests and didn’t follow the white-shirted attackers into the village.

Professor Lo said police would have known it was a triad group involved. Being named as a triad member is a legal offence in Hong Kong so media reporting is cautious of naming individuals. But Professor Lo said it was believed the district council in Yuen Long was controlled by the triad. Mr Ho on Monday denied he was behind the Yuen Long attacks. The Foreign Correspondents Club of Hong Kong urged police to "bring justice" after what they said was an unprecedented attack on citizens at the train station and "a sickening scene of mob violence at Yuen Long". A Democratic Party legislator Lam Cheuk-ting, who was previously an investigator with the Independent Commission Against Corruption, was left with a bloodied face after he went to Yuen Long to help after being tipped off that triads planned an attack on democracy protesters returning to the station. Over 400,000 people had earlier marched peacefully through the city streets. A Catholic activist was among 38 people hospitalised after being attacked at Yuen Long and at least three television reporters were attacked.

Protesters react to tear gas during a confrontation with riot police in Hong Kong on Sunday night. Credit:AP Willy Lam said "the fact that police refused to take action is a very dangerous precedent". He said the violence increased the urgency for Chief Executive Carrie Lam to appoint an independent commission into the extradition bill saga but it appeared she had lost Beijing’s confidence and was unable to take any action. The Hong Kong government released a statement early on Monday condemning the attacks at Yuen Long that had injured commuters and also the graffiti attack by protesters on the Central Government Liaison office in Sheung Wan. The director of Beijing’s liaison office, Wang Zhimin, fronted a televised press conference on Monday to say protesters had challenged Beijing’s authority and he was angry and shocked at the attack on the national emblem.