• Update: Richard Holden was later acquitted and after the jury had unanimously found him not guilty the judge said Holden “leaves the court without a stain on his character”.

A former special adviser to Sir Michael Fallon when he was defence secretary allegedly carried out a “very quick” sexual assault as he gave his victim a “great big hug”, a court has heard.

Richard Holden is accused of sexually touching a woman in her 20s without her consent at a party in London on 17 December 2016.

The 33-year-old, who denies one count of sexual assault, was employed as one of Fallon’s media advisers until early 2017, when he left.

Prosecuting, Sarah Whitehouse told Southwark crown court that Holden had been in a “effusive and lively mood” during the party, and “swept up to” the alleged victim and gave her a “great big hug” as she went to leave with a friend at about 11pm.

He then allegedly groped the woman, putting his hands around her waist before moving his hands up her skirt and touching her intimately.

Whitehouse said it was a “very quick incident”, adding: “Shocking, one might think for her, but not the sort of thing to attract too much attention late at night at a party.”

She told the court that Holden’s flatmate came over and pulled him off the alleged victim, who remarked that he was a “creep”.

Giving evidence, the woman sat behind a screen in court, revealing that she knew Holden and had previously gone out for lunch with him, and had attended the party that night with friends.

Recalling the details of the alleged incident and how he had hugged her inside her coat, she said that she felt as though she was falling backwards towards the wall.

The jury of eight men and four women heard that during the alleged incident, Holden touched the woman intimately underneath her skirt in an ordeal that lasted two to three seconds.

The woman told the court that, before the assault, she had felt “a bit uncomfortable the entire evening”, because Holden kept going up to her and giving her hugs, and telling her how beautiful she was.

She did not report the incident until 1 February 2017. When asked by Whitehouse why this was, she said: “I was still in shock, I could not believe it had happened to me. I did not know it was a crime ... I just thought it was the sort of thing that happened at parties.”

She told the court she had decided to take it further because she “could not risk it happening to another woman”.

The woman said she had not had anything to drink that night, and that Holden “seemed quite drunk” because he was red in the face and gave the impression he was intoxicated.

Holden, of Lambeth, south London, was seated in the dock for the start of the four-day trial on Monday, wearing a dark suit and blue tie. He previously held a number of roles for the Conservatives, and spent several years in the party’s press office.

The court also heard how the pair had exchanged messages in the months before the alleged incident – something that under questioning the woman said was a “bit of banter”.

It was also revealed that Holden’s new girlfriend at the time was at the party. The alleged victim said she knew they were together, and that this along with the hugs he was giving her made her feel uncomfortable.

Eleanor Laws, defending Holden, said during cross examination: “I am going to suggest that he did not come over and hug you repeatedly even once in the evening or even compliment you.”

She replied: “I gave my statement, that is the truth.”

When asked why she did not scream as the alleged incident happened at the party, she said she was “in shock”, adding: “I could not believe someone would do that to me.”

The trial continues.

• Update added 12 June 2018.

