A rape case has collapsed after a 21-year-old student said that she had been too drunk to remember whether or not she had agreed to have sex.
Mr Dougal denied raping the female student
The woman had alleged she was raped by fellow student Ruairi Dougal in a hall of residence at Aberystwyth University.
But High Court judge Justice Roderick Evans directed the jury to reach a not guilty verdict, on the basis that drunken consent is still consent.
Mr Dougal, 20, had told the Swansea court that the sex was consensual.
The woman said she passed out after drinking too much.
Swansea Crown Court heard on Wednesday, that the woman alleged that Mr Dougal, from County Donegal in the Republic of Ireland, had raped her in a corridor outside her room in the halls.
She told the court that she was sure she would not have consented, and if she had wanted sex she would have opened her flat door and taken the man into her bedroom.
But defence barrister Stephen Rees argued it was impossible for her to be sure she had not consented because she could not remember.
After she gave evidence, Huw Rees for the prosecution said he was abandoning the case.
Judge Mr Justice Roderick Evans then instructed the jury to find Mr Dougal not guilty.
During the case, the jury had heard how the female student drank vodkas before attending a party at the arts centre on the university's campus.
She became ill and a member of staff asked Mr Dougal, who was working as a security guard, to walk her home.
She told the court she could remember little else apart from lying on the corridor floor and briefly emerging from unconsciousness to be aware "that something was happening".
The woman complained to police two days after the alleged attack, but it was not until police interviewed Mr Dougal that she was told that she had had full sexual intercourse, the court heard.
"The prosecution has taken stock, in light of the evidence revealed in cross examination," said Huw Rees.
"The question of consent is an essential part of the case. Drunken consent is still consent.
"She said she could not remember giving consent and that is fatal for the prosecution's case."