Asked by Tom Creed, prosecuting, at the Central Criminal Court sitting in Cork, what precisely she took that to mean, the witness replied: “That he would be the first person I had intercourse with.”

She described yesterday how she twice complained to her mother that her brother was sexually assaulting her. Recalling the first time she complained, “My mum said, ‘all you want is for this to stop. We will do that and you don’t have to inform the guards’. He was moved out of the house in March 1997.”

After not getting on well in secondary school up to that point, she said everything started getting better and she “aced” her Junior Certificate.

In December 1997, her brother came back into the family home and the complainant said her brother apologised and said he wanted to make it right.

But she claimed that one time when he was driving her home from an event. he stopped the car in the Marina in Blackrock and got on top of her. She fought him off.

She recalled a second alleged incident when she fell asleep on her way home in the car and woke to find the car had stopped and her brother had pulled down her underwear and put his penis in her vagina. This is the alleged rape to which the accused pleaded not guilty. He also denies 41 sexual assault charges between January 1991 and August 2001 when she was aged between 9 and 20.

She described her father telling her around 2001: “‘You are out of the house, you are over 18, you know how to look after yourself.’ If I went to the guards he made it quite clear I was not coming home.

“My mother begged me not to make a statement.”

The 37-year-old accused pleaded not guilty to a total of 41 counts of sexually assaulting his sister and one charge of raping her.

The complainant, now aged 33, testified that the sexual assaults started by him telling her to take off her clothes. He would look at her vagina, she said, and touch it. The touching then became the insertion of his fingers in to her vagina, she claimed, adding that he would also put her hand on his penis. She said he also tried to get her to perform oral sex but she would never do this.

The case continues.