Deputy Assistant Commissioner Maxine de Brunner was criticised by a tribunal after a row which started when she saw an officer walking around in just a towel led to a case for sexual discrimination

A senior woman police officer who objected to a male colleague walking around wearing just a towel tried to punish a chief inspector because of his unit's 'macho culture', it was claimed.

An employment tribunal found that Chief Inspector Adrian Denby was unfairly punished for failings, while a female colleague in a similar position was not.

The hearing was told that Deputy Assistant Commissioner Maxine de Brunner, one of Commissioner Sir Bernard Hogan-Howe's closest aides, arrived at the unit that Mr Denby was in charge of, 'on a mission to drive out the macho culture'.

Shortly after arriving she encountered an unnamed male colleague in the corridor wearing only a towel around his waist, on his way to the locker room.

The tribunal in North London was told the encounter made her angry and she admitted it was her 'pet hate'.

It is believed Miss de Brunner was so incensed following the incident that Mr Denby, who has had nine commendations and previously had an unblemished police career, feared he was going to be removed from his position.

He was placed under investigation because of alleged malpractice by officers in his unit, including cheating on overtime hours worked and operating an off-licence from in the police station.

It is believed Mr Denby, who was placed on restricted duties and had promotion opportunities curtailed, was criminally investigated.

But it is thought that a female peer in another unit who also came under investigation was not subjected to similar measures.

The Times reported that a string of senior officers gave evidence to try to justify the treatment suffered by Mr Denby, but the judge concluded the force's case was 'marked by a lack of transparency', missing documents and lacking explanations.

The tribunal said Mr Denby's case was 'striking for its unfairness' and concluded that his treatment was down to his sex.

It found the Metropolitan Police guilty of repeated sex discrimination. A damages hearing will take place later this year.

The hearing was told that Deputy Assistant Commissioner Maxine de Brunner (pictured) was 'on a mission to drive out the macho culture' in the Territorial Support Group (TSG) unit in Paddington, west London

At the time of the incident, in September 2014, Mr Denby was in charge of the Territorial Support Group (TSG) unit in Paddington, west London.

The unit was struggling to recover its reputation since the death of newspaper vendor Ian Tomlinson at the G20 protests in 2009.

A spokesman for the Metropolitan Police last night said: 'The MPS took the decision to defend the claims made in this employment tribunal. Now we have carefully considered the judgment we have sought leave to appeal the findings.'

Channel 4 News claimed that of the 62 male officers who have made sexual discrimination claims against the police in the past five years, only seven won their case.

In the same period, 91 out of 374 female officers who made sexual discrimination claims won their cases.

In 2013, Miss de Brunner came under heavy criticism after it was revealed her ceremonial head-dress, a Napoleon-style hat with a black and white feathered plume, cost £660.

In 2013, Miss de Brunner came under heavy criticism after it was revealed her ceremonial head-dress, a Napoleon-style hat with a black and white feathered plume, cost £660

The Met defended the purchase on health and safety grounds, saying the headgear had to be fitted exactly because it has no chin strap.

She was also one of the investigating officers in the elite special inquiry team involved in the case of the former royal butler, Paul Burrell, who was charged with three counts of theft of Princess Diana's belongings.