HONG KONG (AFP) - Hong Kong's police force have long prided themselves as being "Asia's finest".
But their hard-won reputation for honest and impartial policing is at risk from accusations of double standards and brutality following violent clashes with pro-democracy protesters, lawmakers and analysts say.
Video footage showing plainclothes officers beating a handcuffed protester as he lay on the ground created shockwaves on Wednesday, just over a fortnight after riot officers fired teargas for the first time in years at crowds of largely peaceful demonstrators.
Protesters have also accused the police of standing by during repeated attacks by pro-government thugs while using what what they describe as disproportionate violence against their ranks in a series of confrontations in recent days.
"Trust between the police and protesters, which was repaired after the use of tear gas, is gone now," Professor Surya Deva, a law professor at the City University of Hong Kong told AFP.
"The root cause of the violence is the government's use of the police force to deal with a political problem."
The city's police force was created in 1844 after the British took control of the territory from China three years earlier. By the 1960s it was notorious for accepting bribes and even colluding with the city's triad gangs.
Its image was gradually cleaned up following the creation of the the city's anti-corruption watchdog in 1974, which brought some of the most venal officers to book and pushed others into retirement.
Hong Kong's officers have since been lauded for their efficiency and honesty while many of their counterparts across Asia have earned reputations for brutality and graft.
The city remains a remarkably safe place to live with low levels of theft and violent crime, despite huge inequalities.
There were just 8.6 robberies per 100,000 citizens in 2012, compared with 243.7 for New York and 789.8 for Paris, according to government statistics.
But critics say the force's recent handling of ongoing democracy protests risks fatally undermining the good work done over recent years.
"We have to acknowledge that Hong Kong has always been seen as one of the safest and most secure large cities in the world. But it boils down to trust. If you don't trust the police force, more disturbances will flourish," Ms Claudia Mo, a lawmaker from the pro-democracy Civic Party, told AFP.
It was a Civic Party member, social worker Ken Tsang, who was beaten by the police in the video.
Distrust in law enforcement and the political elite is part of a wider malaise among the city's youth, who feel increasingly ignored and unrepresented.
Spiralling property prices, competition from wealthy mainlanders and the coziness of the city's politicians with big business leave many fretting about their future.
But anger has boiled over against officers, particularly after protester crowds were regularly attacked by masked thugs thought to have links to the triads.
Angry chants of "hak ging" - black cops - have now become commonplace among protesters whenever they are confronted by officers, a pun on the phrase "black societies" which is used to describe triad gangs.
To add to the police's embarrassment, some of the officers identified by the local media as being involved in the beating of Mr Tsang comes from the elite Organised Crime and Triad Bureau.
"The biggest thing the police have lost is citizens' trust in them," 19-year-old college student Joseph Man told AFP.
"They say they are professional but we can see they are starting to lose control of their minds."
The police have defended their actions as restrained in the face of increasingly hardcore protesters determined to take over new areas of an already disrupted city.
They have strongly rejected any suggestion of collusion with triad gangs and say they have suspended seven officers involved in the beating video pending an investigation.
Mr Sonny Lo, a political analyst at the Hong Kong Institute of Education, said the city's police force is trapped in a "political sandwich" between protesters, the government and an increasingly impatient public.
"These protests have to be solved politically. The police can't deal with politics, they are just an arm of the government," he said.
But Mr Lo warned continued confrontations could see China resort to sending in the People's Liberation Army.
"If police can't handle these protests more skillfully or more decisively I'm afraid that the worst case scenario - namely the requirement of the PLA to intervene - will not be impossible," he said.