A compulsory retirement means the 44-year-old, who was last deployed at the traffic investigation and support division in Kowloon East, will still receive his pension, and other retirement benefits, when he reaches 55.

Speaking to the media last month, Lo was adamant about the importance of his officers maintaining the highest standards of integrity.

“Any black sheep has to go,” the source said. “We have tightened our disciplinary mechanism. The recent harsh punishment is a warning to all our colleagues that there will be no leniency for those who breached disciplinary rules.”

The source said in the past Pannu’s misconduct would have merited a written “warning for dismissal”, which would mean an officer would be expelled if they stepped out of line again.

Integrity of Hong Kong police must not be compromised

“Now we must maintain and uphold integrity in the highest standard, as the police chief said. Pannu’s misconduct had undoubtedly brought disrepute to the force,” the source added.

The internal investigation against Pannu began after a female inspector filed a sexual harassment complaint in 2016, following an incident in December 2015.

The female inspector said she received two close-up pictures of male genitalia from Pannu when she was driving home from the party at Kwun Tong police station, where Pannu was also based.

Pannu is said to have called her to see if she had received the pictures, and followed that up by sending her a 12-second video of a naked woman.

So far in 2018, 15 police officers have been disciplined for a variety of offences.

Pannu, who was born in Hong Kong, joined the force in 1995. In a 2015 media interview, he said he was a third generation ethnic Indian from a family of officers, and his father and grandfather had also served in the force.

He called being a policeman a meaningful and heroic job, as it enabled him to seek justice for the victims of crime.

Concerns raised as 26 Hong Kong police officers arrested in 2018 so far

The city’s police force has faced a growing integrity crisis, with an increasing number of officers being arrested. In the first half of the year, an average of one officer a week has been arrested.

According to the police, 15 officers were found guilty of disciplinary offences in the first four months of this year, compared to 43 in 2017, and 50 in 2016.

A police spokesman said punishments had ranged from a caution, to dismissal without retirement benefits, while one officer was sacked outright, although the spokesman declined to provide details of that case.