The Metropolitan Police have not learned the lessons of the Macpherson report, a black female officer who has taken the force to an employment tribunal said today.

The 1999 report into the investigation into the murder of black teenager Stephen Lawrence branded the Met "institutionally racist".

Today Police constable Carol Howard told the tribunal hearing: "There has been a blatant cover-up by the Met. The police have not learned any lessons from the Macpherson Report and they still continue to discriminate."

The 34-year-old, a firearms officer in the Diplomatic Protection Group (DPG), is claiming direct discrimination on grounds of race and/or sex and/or marital status, and is also claiming harassment and victimisation.

Her witness statement to the hearing in central London said that her career as an authorised firearms officer (AFO) was disrupted when Acting Inspector Dave Kelly was posted to DPG in December 2011.

"From then on, I was targeted, subjected to detrimental treatment and harassed by Acting Inspector Kelly's actions in comparison to male and/or non-black colleagues."

She was one of only two black women out of 700 officers in the group, she said.

During the time when she was allegedly receiving less favourable treatment than others from Mr Kelly, he was acting up from his rank of Sergeant, to which he has now reverted, she said in her statement.

"It was evident that the other sergeants found him annoying, and .. he was often referred to as the 'little weasel' by supervisors."

Mr Kelly made it difficult for her to get time off from her work with DPG to deal with a trial left over from her previous role in the Child Abuse Investigation Team, and also conducted a "completely unnecessary and very heavy handed" interview with her when she had been off sick.

He also invited her to join him for shooting practice.

"I was really upset that he was making me look incompetent amongst the guys especially as I had worked hard not to stand out."

In June 2012 a sergeant asked her to take part in a photo shoot in the London Evening Standard.

She was led to believe it was happening purely to highlight the Olympics, but there were questions about the reputation of firearms officers.

She was aware that an investigation was taking place into the shooting of Mark Duggan by police.

She said: "I felt that I had been singled out and chosen, as a black officer, to represent diversity and to change the public image of white police shooting black youth."