A man jailed for damaging a Claude Monet painting estimated to be worth €10m has lost an appeal against conviction.

Andrew Shannon (aged 50), of Willians Way, Ongar, Dublin 15 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.

Shannon was directed to be found not guilty of damaging two paintings at the Shelbourne Hotel on January 8, 2014 but was found guilty of the National Gallery incident by a jury at Dublin Circuit Criminal Court.

Judge Martin Nolan sentenced him to six years imprisonment with the final 15 months suspended on December 4, 2014.

He lost an appeal against conviction today with the Court of Appeal holding that his trial was satisfactory and his conviction safe.

Giving judgment, Mr Justice John Edwards said the National Gallery incident concerned damage to an 1874 impressionist paining by Claude Monet, 'Argenteuil Basin with a single boat', estimated to be worth €10,000,000.

Shannon had entered the gallery on the date in question and was observed standing in front of the Monet painting.

He was captured on CCTV moving forward in the direction of the painting with his arm raised and striking the painting, causing a substantial tear to it.

The State's case was that the damage was premeditated and deliberate.

Shannon, however, contended that he had fallen accidentally after suffering a coronary episode.

On January 8, 2014, Shannon and his nephew were in the Shelbourne Hotel.

There had been a function taking place in the “Deirdre and Arms suite” of the hotel, in which two large paintings by the artist Felim Egan were hanging.

When the function was over and the participants, as well as two staff members, had left, the paintings were undamaged.

Shannon and his nephew were recorded on CCTV as being in the vicinity of the suite before leaving the hotel at 7pm.

Some time after this staff members returned to the suite and found two Felim Egan paintings had been damaged. They appeared to have been torn or possibly slashed.

Shannon maintained that he had merely been visiting the hotel's spa facilities but was later charged with criminal damage.

He faced trial on the National Gallery but the jury in that matter were unable to reach a verdict.

Later, he faced trial on both incidents together but his lawyers applied for separate trials.

Mr Justice Edwards said the trial judge correctly exercised his discretion not to sever the indictment and allow proposed evidence from the Shelbourne Hotel incident to be relied upon in the case involving the National Gallery incident and vice versa.

It was properly characterised as system evidence, the judge said.

After the granting of a direction to acquit in respect of the Shelbourne Hotel incident, Mr Justice Edwards said the trial judge was correct not to discharge the jury.

After the direction to acquit, the jury were given “explicit and crystal clear” instructions that they were to disregard all evidence in relation to that incident.

Mr Justice Edwards said the incidents were separated in time and place and there was no overlap of witnesses.

Furthermore, it was made clear to the jury from the outset that evidence relating to the two incidents was to be considered separately from one another.

Mr Justice Edwards, who sat with Mr Justice Garrett Sheehan and Mr Justice Alan Mahon, said the trial was satisfactory and the conviction safe.

The appeal was therefor dismissed.

After the judgment was read out, Shannon said he would “like to appeal to the Supreme Court”.

Earlier, counsel for Shannon, Michael Bowman SC, said his client was being charged with two separate and distinct instances – the causing of damage to a painting in the National Gallery and subsequently the alleged causing of damage to a painting in the Shelbourne Hotel.

Mr Bowman said the prosecution had not been able to sustain a conviction on the first incident in the National Gallery – a jury failed to reach a verdict - when the second incident in the Shelbourne Hotel allegedly “fell into their lap”.

By facilitating the prosecution to merge and run two trials together, a fair trial became impossible, Mr Bowman submitted.

With the second incident, he said the prosecution now had the missing piece of the puzzle.

They were taking the mindset and motive from the first incident to allegedly prove that Shannon had “something against paintings” and “liked to put holes in paintings”, Mr Bowman said.

They thought they could prove the second incident by using the first incident “and vice versa”, Mr Bowman said quoting from transcript.

For technical reasons, he said the DPP weren't allowed to do what they did.

Mr Bowman further submitted that once the trial judge directed the jury to find Shannon not guilty of the Shelbourne Hotel incident, he erred in failing to discharge the jury at that point.

A full-blown case was run in front of the jury for three days with 15 witnesses and it was hard to conceive of something as prejudicial, Mr Bowman submitted.

Counsel for the Director of Public Prosecutions, Kerida Naidoo SC, said Mr Bowman could not point to any authorities for his proposition that it was impossible to get a fair trial.

Mr Naidoo said the case was opened to the jury on the basis that they were to treat both cases separately and only if they got to a cartain stage could they look to see what they could learn from putting the two cases together.

The jury were ultimately told that Shannon was not guilty of the Shelbourne incident, Mr Naidoo said, and Mr Bowman was suggesting that the jury ignored that direction.

In law, Mr Naidoo said, the starting point was that juries do not ignore directions from judges and honour their oaths.

He said there was an abundance of evidence to establish that what had happened in the National Galley was done deliberatly.

He said two eyewitnesses, from New Zealand, said they saw Shannon punching the painting and expert evidence established the force of the blow.

Shannon had a bag with him with a tin of paint stripper in it and when he fell, as he claimed, he did not drop the bag containing the tin of paint stripper, Mr Naidoo said.