Patrick James (PJ) Mansfield, son of the late billionaire Jim Mansfield, has gone on trial at Dublin Circuit Criminal Court charged with the unlawful possession of over 1,200 bullets.

Mr Mansfield (41) denies possessing 1,252 rounds of .22 calibre ammunition without the relevant firearms licence at his former home in Coldwater Lakes, Saggart, Co Dublin on January 29th, 2015.

Mr Mansfield’s current address was given as Saggart House, in Saggart.

On the opening day of the trial, the court heard that gardaí­ searched the house and found a legally-held Walther .22 pistol with a bullet in the chamber behind a picture frame in the master bedroom.

A 12-gauge shotgun, also licenced, was recovered from a locked gunsafe in the wardrobe of a dressing room, along with a large quantity of ammunition in various locations.

In total, gardaí­ found 1,557 rounds of .22 ammunition, however, Mr Mansfield’s licence only permitted him to hold 300 such bullets.

The excess of 1,257 bullets was seized by gardaí­.

A further quantity of 98 rounds were found for the 12-gauge shotgun, but these were permitted by licence.

Detective Sergeant Brendan Flanagan told Derek Cooney BL, prosecuting, that gardaí­ executed a search warrant at the house on the morning in question.

Mr Mansfield and his girlfriend Julianna Husman were present at the time.

Detective Garda Maria Flynn told the court that she found the shotgun inside a tall safe in a walk-in wardrobe area, along with several boxes of .22 pistol bullets and shotgun cartridges.

She said the Walther pistol found behind a picture frame in the main bedroom contained one bullet in the breech, or chamber; and a further nine rounds in the magazine.

Det Gda Flynn said she made the gun safe by taking out all the bullets.

Detective Garda Nigel Petrie said he found 120 rounds of .22 ammunition in a drawer in the garage, and a further quantity of bullets in the gun safe.

Det Gda Petrie said he separated out the total of 1,557 rounds of ammunition and returned the permitted 300 bullets to Mr Mansfield, seizing the excess.

Det Gda Petrie agreed with Bernard Condon SC, defending, that Mr Mansfield had co-operated fully with the search, unlocking the gunsafe and telling gardaí­ about the pistol behind the picture frame.

Opening the trial, Judge Cormac Quinn warned the jurors not to Google anything or conduct any searches on social media or other electronic communication, but simply to decide the evidence on the basis of what they heard within the four walls of the court.

The trial continues.