On trial: Married policeman Robert Dawson, 49, (pictured outside Southwark Crown Court today) denies a charge of misconduct in a public office

A married policeman seduced a rape complainant with wine, pizza and text messages while gathering evidence to arrest her alleged attacker, a court has heard.

Detective sergeant Robert Dawson, 49, had sex with the woman after texting her ‘ U R not alone... I think U R so brave, I wish I could do more,' it was claimed today.

The ‘bad boy’ officer used his police phone to flirt with her by text but was unaware the ‘unstoppable diarist’ was keeping a daily record of their fling.

Dawson admits having sex with the rape complainant once but claims he was comforting her as a friend, Southwark Crown Court was told.

He denies a charge of misconduct in a public office between August 17, 2010 and November 30, 2010.

Prosecutor Samantha Cohen said: ‘ Mr Dawson is a police officer, he worked on a specialist rape investigation team during 2010 called the Sapphire Unit.

‘In May of that year he was appointed into the position of investigating officer in an allegation of rape made by a woman against a colleague of hers from work.

‘His role was to investigate the crime that she had reported, so he was to collect evidence, interview potential witnesses and to potentially make an arrest, interview a suspect and then to pass to the Crown Prosecution Service.

‘He became very close to the complainant as his investigation progressed - far too close, we say.’

Dawson had access to her medical records that showed a history of ‘severe depression and self-harm’ and in turn she opened up to him about her feelings of inadequacy and distress.

‘He could have been under no illusions that she was disturbed,’ said Ms Cohen.

The CPS ultimately opted not to press rape charges against the assailant but Dawson told her he disagreed with their decision and appealed, it was said.

The alleged victim had taken the CPS decision ‘very hard’, jurors heard.

Ms Cohen said: ‘ As he steered her case through that appeals procedure within the CPS he maintained very regular contact with her.

‘He would visit her alone at her home, take bottles of wine with him and took a video for her to watch on one occasion.

‘They became sexually intimate and finally had intercourse.'

But unknown to Dawson the ‘unstoppable diarist’ kept a daily record of their affair and some text messages stored on her computer, it was said.

Accused: The detective sergeant had sex with a rape complainant after texting her ‘ U R not alone... I think U R so brave, I wish I could do more,' it was claimed at Southwark Crown Court (pictured) today

The sergeant started to text her while he was on holiday in August, writing ‘ U R not alone, I am here and always will be. I think U R so brave, I wish I could do more’ , the court heard.

Other texts, littered with smiley faces and kisses, assured he he was ‘there for her all of the time’ and that he would do whatever it took to get her alleged attacker prosecuted.

Other messages urged her to ‘trust me x’ or simply wished her ‘nite x’, it was said.

The complainant became ‘confused and anxious’ writing in her diary that their ‘spiralling’ relationship ‘freaked me out’.

‘I feel so stupid about him, mostly because of boundaries. I pushed it but then he let me and then stopped it,’ she wrote.

He became very close to the complainant as his investigation progressed - far too close, we say Prosecutor Samantha Cohen

Ms Cohen said: ‘She, you may conclude, was disturbed by what was happening between her and the policeman who was charged with investigating the crime she was alleging.’

By September 28, 2010, the officer and the rape complainant had embarked on an intimate relationship, the court heard.

‘He hugged me and kissed me on the cheek when he left and felt nice,’ she wrote in her diary after finding out her appeal was not going to plan.

‘We had a bottle of wine which he went to get from the car because I couldn’t speak.'

On his work log, Dawson simply noted he had ‘attended her home address this morning and informed her that the CPS had reviewed the case’.

Two days later, the complainant’s diary says: ‘He said he could keep me distracted, had to resist the urge to say something inappropriate!

‘Turns out I didn’t need to, we had some wine, ordered some pizza and talked and we watched the Hangover.

‘I came back from the toilet and he had moved closer, he had his hand on my thigh and there was no mistaking that for being friendly... he definitely has that bad boy feel about him.’

Arriving at court: Dawson admits having sex with the rape complainant once but claims he was comforting her as a friend, jurors heard

Dawson paid her more visits on October 4 and 15 and begged her by text: ‘If you still in bed could you say something rude :) x,’ the court heard.

Ms Cohen said: ‘Mr Dawson you may think by this stage was interested in her - who he only had contact with by the virtue of his role as a police officer - in an entirely sexual way.’

On October 25 Dawson told the woman he was married and ‘shouldn’t be doing this’ but went on to have sex with her.

She wrote he was a ‘cheeky git’ following the liaison that Dawson admits.

But Dawson denies sleeping with her for a second time.

Ms Cohen said: ‘Mr Dawson says yes I was a police officer, yes I did investigate her allegation, yes I did visit her at home, drink alcohol with her, I did have sexual intercourse with her although not to the extent she says.

‘He says I did not realise she was vulnerable and anyway I did those things not in my capacity as a police officer but in the capacity of a friend, somebody offering her comfort and at her behest.

‘He took advantage of her when she was at her lowest point.’

She added: ‘The Crown say that this defendant took advantage of the complainant, he did so whilst he was the holder of a public office and it is disingenuous for him to claim that these meetings had nothing to do with his job as a police officer.

‘The only reason he had any contact with her was because he had been the investigating officer in her case and he was keeping her updated about and trying to pursue for her all possible avenues of appeal.’

Dawson, of Chelmsford, Essex, is on unconditional bail throughout the course of the trial.

He was investigated by the Independent Police Complaints Commission over his behaviour while based in Stratford, east London.