The father of the woman subjected to a sex attack by businessman Anthony Lyons says he has not shown any meaningful remorse.

Lyons left Arbour Hill Prison this morning, after serving just six months for a sexual assault.

Lyons (53) from Griffith Avenue in Dublin attacked a then-27-year-old woman as she walked home in north Dublin on October 3rd, 2010.

He later claimed that a combination of alcohol, cholesterol medication and cough syrup had given him an "irresistible urge", which overcame him.

The Court of Criminal Appeal heard back in 2014 that he made a €200,000 settlement with the woman.

However, Mr Justice John Murray said the court did not consider that to be a relevant mitigating factor.

Lyons had been sentenced to six months initially, but a further 18 months was later added to that sentence.

The Court of Criminal Appeal quashed his original sentence - deeming it 'unduly lenient'.

His victim's father has criticised the judicial system and says Lyons never showed remorse for he did.

"The word 'sorry' was used just once by his legal team in court - he never had to take the stand, he never had to speak" he told the Pat Kenny Show here on Newstalk.

"He tried to stop my daughter from taking the stand, but she was brave enough to take the stand".

"And he has never shown any remorse as far as I'm concerned - you can't ask you legal team to say sorry for you, and you're standing there pleading not guilty".

"It doesn't make sense" he added.