A teenager denies raping his step-sister while they were home alone.

The man, who we are not naming in order to protect the identity of his alleged victim, is said to have carried out the assault in late 2018 when his father and step-mum had left him to look after his step-sister. The girl is three years younger than him.

Opening the case at Swindon Crown Court yesterday, prosecutor Mary Aspinall-Miles said: “The prosecution case is very straightforward. They’d never been left alone together before like that and for whatever reason – and the prosecution don’t have to prove why – this defendant used the absence of the parents and the complainant’s isolation to rape her and to take advantage of her.”

She added: “There was no reason to suspect or think anything untoward would happen and certainly not between somebody that the complainant saw and liked, maybe even loved, as a brother.”

It was said the girl had been watching a film in the living room when the older boy, who was over 18 at the time, came in and sat on the other sofa.

He shifted to the sofa on which she was sitting and began touching her leg. She told him to stop, but he carried on pestering her. Not saying a word, he first touched her sexually then raped her, it was said. The assault lasted a couple of minutes before he pulled up his boxer shorts and went to his room, Ms Aspinall-Miles told jurors.

“The complainant was left in shock and immediately after went up to her bedroom and then avoided the defendant for the rest of the evening,” she said.

The prosecutor said the girl had frozen, but she warned the jury not to make assumptions.

“The learned judge will direct you in due course about stereotypes because everybody has a view or thinks they know how they might react or somebody they know might react in a situation like this; a rape situation,” she said.

“The most common misconception is that people fight back. Television helps with that because they constantly push that image onto you.

“It’s the experience of the courts and your own common sense that people will react to situations in very different ways. Some people fight, some people run and some people freeze. And what the complainant says is that at that point she froze.”

The girl had not told her parents about what had happened. Her mum only found out the following February when she was told by her daughter’s friend.

The defendant’s step-mum and father confronted him about it, Ms Aspinall-Miles said. Under pressure from them, he was said to have admitted he had had sex with her.

Later interviewed by detectives, he gave a prepared statement claiming the sexual contact between them had been consensual.

The man, still in his late teens and from Swindon, denies rape and sexual assault by penetration. The trial continues.