A Dublin man has been given a six year sentence after being convicted of damaging a Claude Monet painting estimated to be worth €10 million at the National Gallery of Ireland.

Andrew Shannon (49) of Willians Way, Ongar had pleaded not guilty to damaging the Claude Monet painting entitled Argenteuil Basin with a Single Sail Boat (1874) at the National Gallery of Ireland on Clare Street on June 29, 2012.

A jury of seven women and five men returned a verdict of guilty on that charge this afternoon following almost one and a half hours of deliberation on day eight of the trial.

The court heard Shannon has 48 previous convictions in this and other jurisdictions some of which are for burglary and theft offences involving antiques. In November 2011 he was sentenced in Wicklow Circuit Court for handling stolen property involving maps dating from 1651 with a value of €6,000.

The Monet painting is now back on display in the National Gallery following a period of restoration.

Judge Martin Nolan imposed a sentence of six years and suspended the final 15 months on strict conditions including that Shannon not enter into a public painting gallery or any other institution or building where paintings are publically displayed.

The maximum sentence for this offence is ten years.

Judge Nolan had earlier directed the jury to find Shannon not guilty of damaging two paintings at the Shelbourne hotel on January 8th, 2014.

Garda Conor O'Braonain told Kerida Naidoo BL, prosecuting, that Shannon had entered the gallery just before 11am and had gone to where the painting was on display. He left and returned a short time later and appeared to fall forward striking the painting.

The point of impact was above eye level and to the left hand side of the painting.

Shannon said he had been dizzy and had fallen forward. He had spoken to a number of people, including two tourists from New Zealand and security staff, at the scene telling them he had a heart condition.

He was treated by a paramedic who reported his vitals were normal and he was given GTN spray and aspirin.

During interview he told gardai he had a heart condition and that’s why he had fallen down.

Gda O'Braonain agreed with Mr Bowman that Shannon suffers from significant heart difficulties. He agreed the accused had qualified as a French polisher.

Mr Bowman said Shannon had been in custody since the date of offence except for a six week period and suffers on-going health difficulties which have not been eased by time in custody. He asked the court to give him credit for time in custody.

He commented that the two year period of restoration for the painting coincided with the amount of time Shannon had spent in custody.

Judge Nolan said he would not expect Shannon to know the value of the painting but he must have known the painting was valuable and historic. He said it was a “peculiar crime” and it was “abnormal” to cause damage in the way he did.

He said he was taking into account Shannon’s age and medical condition in sentencing. He said all time the Shannon had spent in custody should be taken into account.

A previous jury in the case had been discharged last December after failing to reach a verdict.

During the trial tourist Michael Kelly Williams said he had seen a man with a clenched fist put it straight into the Monet. He said he grabbed the man, who said something like he felt faint, and moved him into the middle of the room to get him away from the paintings.

His wife Toni Ashton said that she was standing beside her husband when she saw an arm appear and a fist go through the Monet. She said it was like a "hammer" and described the movement as a lunge.

The jury viewed CCTV footage of the incident in the National Gallery and heard from security staff who had called gardai and an ambulance.

Paramedic Gordon McArdle gave evidence that after he was called to the gallery Mr Shannon told him he had unstable angina.

Mr Shannon said he had chest pains, had collapsed and fallen against the painting.

He said there was a tin of paint stripper in Mr Shannon’s bag which he said he had as he was a French polisher.

Mr Shannon was interviewed by gardai after being released from hospital later that day. He was seen by a number of doctors during his detention and later returned to hospital.

During interview he told gardai he had a heart condition and that he had done nothing wrong.

Consultant surgeon Nicholas Walcot gave evidence that in July 2013 Mr Shannon underwent a quadruple heart bypass and that he had 90% blockage in three vessels of the heart and one was completely blocked.

Mr Walcot had agreed with Mr Naidoo that he would expect only 1% of people with Shannon’s heart condition to have dizzy spells and that if he fell down he would have expected him to stay down rather then get up.

The jury had also viewed CCTV from January 2014 showing Mr Shannon entering the Shelbourne hotel with a second man and walking around various locations.

Mr Shannon told gardai that he was only on the premises to visit the hotel spa and had not caused any damage to the paintings

The paintings by artist Felim Egan were entitled 'Morning Strand' and 'Evening Strand'.

Banqueting manager John McLoughlin said he had been on duty at a function in another suite and was standing at the door greeting guests when an older and younger man came along the corridor and passed him. He said there was no CCTV inside the function rooms.

He was later cleaning in the room where the paintings were hanging when he noticed white threads hanging from the blue painting. He said a colleague drew his attention to damage to the other painting. He said the paintings had not been damaged earlier that evening.

Eamon Kelly, loss prevention manager at the hotel, said he began to review CCTV when he returned from holidays on January 14th, 2014 and gave the disk to gardai the following day.

Mr Kelly agreed with Michael Bowman BL, defending, that before he came back from his holidays no one had contacted gardai or treated the room as the scene of a crime. The room had also been used during that time.