Two New Zealand tourists have described how they saw a man’s fist go through a Monet painting estimated to be worth €10 million in the National Gallery two years ago.

The jury have also heard from security staff and a paramedic who attended at the scene shortly after the incident.

The court heard the accused man told witnesses he was faint after the incident, complained of chest pain and said he had fallen against the painting.

Andrew Shannon (50) of Willians Way, Ongar, Dublin 15 has pleaded not (NOT) guilty at Dublin Circuit Criminal Court to damaging one 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.

He further pleaded not guilty to damaging two Felim Egan paintings – 'Morning Strand' and 'Evening Strand' at the Shelbourne Hotel on January 8, 2014.

Michael Kelly Williams told Kerida Naidoo BL, prosecuting that he and his wife, Toni Ashton, were on holidays in Ireland and visited the National Art Gallery on the morning of June 29, 2012.

He said they arrived about 10.15am and went through the gallery viewing Irish works on the first floor and through the rooms displaying early Renaissance works until they reached the room where the Monet was displayed.

Mr Kelly Williams said he was standing looking at a painting when to his right hand side he saw a man put his fist through the Monet, straight into the middle of the painting.

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.

Mr Kelly Williams said the man had a clenched fist and put it straight into the painting.

He said that in his work as a flight attendant he had treated people feeling faint before and on the basis of his experience he formed the view that the man was in no way suffering from feeling faint.

He said after moving the man into the middle of the room he had his hands on the man’s shoulders and he called for security.

The couple were later interviewed by gardai and gave a statement.

Ms Ashton told Mr Naidoo 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.

She said the man said he fell faint and later said he had a heart condition and wanted water.

Mr Kelly Williams agreed with Michael Bowman SC, defending, that he had been angry about what he had perceived to have happened and it was his view the man was doing it on purpose.

He agreed on viewing the CCTV of the incident that his hands had not been on the shoulders of the accused holding him in the seat after the incident and his recollection in that regard was not entirely correct.

Mr Bowman said that within 12 months of the incident Mr Shannon had undergone open heart surgery and a quadruple by-pass.

He said it was found 90% of his arteries were blocked.

Ms Ashton told Mr Bowman that Mr Shannon seemed disorientated and there was no eye contact. She agreed he was not aggressive.

Paramedic Gordon McArdle told Mr Naidoo that when he attended at 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 he asked Mr Shannon what was in his bag and found he had a tin of paint stripper. He ran a series of tests in the ambulance and overall found him to be quite stable and his vital signs did not cause concern.

He said he administered aspirin and GTN spray as he was complaining of chest pains.

Mr McArdle asked Mr Shannon about the paint stripper, as he was concerned he may have ingested some, and the accused replied that he had it because he was a French polisher.

The trial continues before Judge Martin Nolan and a jury of seven men and five women.

Peter Judge, a security guard at the National Gallery, told Mr Naidoo that he was on patrol when he heard a loud bang and people roaring and shouting in room 10.

He said he went to the room and asked Mr Shannon what he had done. He said Mr Shannon said he had pains in his chest and wanted to get out.

Mr Judge said he told Mr Shannon he was not going anywhere and he replied he was going to have a heart attack.

He said the head of security came in and took over proceedings then gardai and ambulance arrived.

Christiaan Clotworthy, head of security at the gallery, said he went to room 10 after being told a man had collapsed and a painting had been damaged. He said he calmed the situation down.

He said the man was agitated and was saying it was an accident. He said the man was asking for GTN spray and water. He said the man fumbled with his phone and dropped it.

Mr Clotworthy agreed with Mr Bowman that in his view the incident was no accident and said the damage to the painting had been "shocking.

He agreed with Bowman that his immediate thought had been that the painting was written off and that he had been wrong.

He did not agreed that his second thought, that this had been no accident, was also wrong.

He said his view was this had been a security incident and he had never read it as a medical one.

Mr Clotworthy said he had dealt with people before who had fallen ill and this man did not behave in a way he would expect.