An inquiry has been launched into the incident involving the Union Moon cargo vessel and the Stena Feronia, which happened close to the Fairway buoy on the Co Down coast at around 7.45pm.

There were 51 passengers and 47 crew members on board the Stena ferry - none of whom were injured.

The ferry had left the Merseyside's Birkenhead on a morning sailing and was on the final stretch to Belfast when the collision took place. Both vessels received substantial damaged.

The Maritime and Coastguard Agency, the Marine Accident Investigation Branch and the PSNI are now carrying out investigations.

Police have charged a man with excess alcohol by the master of a ship.

The 55-year old man - who was onboard the Union Moon - has been charged under section 78 of the Railways and Transport Act of 1973.

He was detained on Wednesday evening and is expected to appear at Ards Magistrates' Court on Friday.

Robert Steventon, Maritime Coastguard, said a disaster was avoided.

"People were very lucky, it could have gone either way - again when you look at the damage of the vessels."

He said all involved were "very, very lucky indeed."

Gintaras Urbeitis, a Lithuanian lorry driver, was a passenger on board the Stena Feronia.

He was in the ferry's restaurant when he heard a loud bang.

Mr Urbeitis told UTV that everyone on board was "very scared."

"What happened nobody knows."

He said the crew members handed them lifejackets after the collision.

Mr Urbeitis added that although he had seven year's experience of travelling for his work, it was the "first time anything like this had ever happened."

Kevin Baird is a member of the Bangor lifeboat team which sped to the scene.

"The water was quite choppy, it was blowing from the west. When you're called out to a casualty that's a ferry, you always have concerns in the back of your mind," he said.

"But when we arrived there, the ferry had already berthed at Belfast and we were more concerned about the safety of the crew aboard the cargo vessel."

Diane Poole from Stena Line told UTV all passengers were discharged safely.

She said:"The staff looked after the customers extremely well onboard.

"There was nothing else that the staff could have done for them and I hope they find comfort in that."

Continental Ship Management, a Norwegian company which owns the Union Moon, is sending a representative to Belfast to assess the situation.

Fleet Manager Runar Mirvold declined to discuss the collision saying the case "is under police investigation", but added that they would comment later.