A domestic violence victim who was sexually exploited by a police officer responding to a 999 call is suing the Metropolitan police for gross abuse of power.

Although the police constable was on duty and in uniform, and has been convicted of criminal misconduct and dismissed from the force for what he did, the Met is refusing to accept any responsibility for his actions.

The woman will appear at Central London county court on Monday to relive her ordeal in front of the former officer as she fights for compensation from the Met.

She alleges that the officer, PC James Formby, plied her with drink and made sexually suggestive comments to her after a 999 call for help following an attack by her boyfriend.

When she was so drunk she was incapacitated, the officer initiated sexual activity with her. The following day the 38-year-old woman was so horrified by what had happened she called the police immediately to inform them.

Lawyers for the woman allege the officer grossly abused his position of power. Documents outlining the claim state that in engaging in "sexual behaviour with the claimant" PC Formby "intentionally abused his position of trust as an on-duty police officer".

The papers allege Formby was "recklessly indifferent" to the fact the woman was a vulnerable victim of domestic violence who was clearly upset after being physically assaulted by her boyfriend, and who had called the police in order for them to protect her.

The officer also knew or was recklessly indifferent to the fact that he was taking advantage of a vulnerable woman who was very drunk and that it would be gross misconduct for him to engage in any sexual activity with her, the woman's lawyers claim.

The case was highlighted by the Guardian in a series of reports which lifted the lid on the scandal of police officers who abuse their position of power to prey on vulnerable women.

Met police lawyers are fighting the woman's claim and refusing to accept responsibilty for the actions of one of their officers while on duty.

It is understood they claim the woman had capacity and consented to the sexual activity, and there was no unlawful act. The officer – although on duty – was on a mission of his own and they are not vicariously liable, the Met argues.

Papers submitted to the court state that the woman, who cannot be named for legal reasons, was drunk and vulnerable when two Met officers answered an emergency call in September 2009 after an assault by her boyfriend.

One of the officers who responded arrested her partner while the other, Formby, then 31, stayed at her home in Greater London to take a statement.

The woman told Formby her boyfriend had pulled her out of a nightclub and assaulted her by throwing her onto the floor and grabbing her around the neck.

She told Formby she was scared and was willing to support a prosecution and attend court if necessary.

As she made her statement to the officer, the woman, who was already drunk, said Formby repeatedly filled her glass with alcohol.

She claims he made sexually suggestive remarks to her and that when she got up to go to the toilet, he followed her, opened the toilet door and watched her, making a comment about a body piercing she had.

When the statement was completed the woman said she told Formby she was too drunk to read it, and asked him to read it to her, which he did.

Shortly afterwards the woman said Formby put his hand down her leggings and later took her into the bedroom where he asked her to perform a sex act on him, which she admits she did.

When the woman sobered up she became "frightened, upset and confused" about the sexual contact which had taken place.

She immediately called the police station and told them what had happened and an investigation into Formby's behaviour was initiated.

Formby admitted misconduct in public office at Southwark crown court in 2010 and was given a 20-week suspended jail sentence. He was subsequently dismissed from the Met.

The woman's case is one of the first taken against the Met for alleged abuse of power involving sexual exploitation by one of their officers.

Other forces have faced similar claims. In Northumbria, where the former constable Stephen Mitchell was jailed for life in 2011 for raping and sexually assaulting a number of vulnerable women, the force has settled seven out of 13 claims for £206,040 in total.

But in four of the remaining cases the force is refusing to accept liability for the behaviour of their officer.

A Metropolitan police service spokesman said: "The officer pleaded guilty at court and has been dismissed from the MPS.

"We are aware of a civil action being taken against the MPS, due to commence at Central London county court on 24 March. We will be defending this action."