A university student who sexually assaulted a woman while travelling on a night bus home from Dublin city is going back to jail nearly a year after his prison term expired.

The Court of Criminal Appeal has increased the sentence for the 24-year-old man by 3 years after the Director of Public Prosecutions (DPP) successfully argued that his original penalty was too lenient.

The father of one was convicted by a jury of sexually assaulting a woman who fell asleep on a night bus home from Dublin city in the early hours of January 9th in 2011.

He received a 2-year sentence with one year suspended from Dublin Circuit Criminal Court which the DPP today appealed on the ground that it was too lenient.

The court has accepted the Director's submissions and has called the crime 'opportunistic, predatory, cheap, sordid and degrading'.

The former student from Nigeria finished doing time nearly a year ago but the court has now added another 3 years to his sentence - one of which it suspended.

His lawyers argued returning to prison will be a disaster for the 24-year-old who held his hand to his head as he was told to present himself at Mountjoy Prison in 4 weeks time to begin another 2 year stretch in custody.