How many Irish fought at the Battle of Waterloo? A lot has been the consensus of historians who have studied this most pivotal battle of the 19th century, but no definitive figure has been arrived at.

Irish army officer Lieutenant Colonel Dan Harvey now believes he can produce as definitive a figure as can be ascertained at this remove 200 years after the event based on his own research and that of others.

Lieut Col Harvey’s book A Bloody Day - The Irish at Waterloo will be published this Thursday, which marks the bicentenary of the battle that ended Napoleon’s career and ushered in a long period of peace in western Europe.

He estimates that 8,500 of the Duke of Wellington’s 28,000 British soldiers, including Wellington himself, or 30 per cent of the total, were Irish. Based on a casualty rate of 25 per cent it can be ascertained that at least 2,000 Irishmen were killed or wounded at the Battle of Waterloo.

On Wednesday night An Taoiseach Enda Kenny attended a charity banquet in the Guildhall in London on the eve of the Waterloo 200 centenary. He did so to honour the Irish involved who fought in the battle.

Some 37 per cent of the 1st Regiment of Foot (infantry) and 27 per cent of the 32nd Foot were Irish, according to earlier research carried out by Maynooth student Peter Molloy based on the battalion books which listed places of birth.

These were not Irish regiments but had a high percentage of Irish within them as did most of the British army at the time.

In addition there were three Irish regiments at Waterloo, the 27th Foot (Inniskilling Fusiliers), the 6th Inniskilling Dragoons and the 18th (King’s Irish) Hussars.

The 27th Foot bore the brunt of Napoleon’s frontal assault and suffered 481 men killed or injured.

Many Irish distinguished themselves at Waterloo. Corporal James Graham from Clones, Co Monaghan, is the man credited with closing the gates of the chateau at Hougoumont on the advancing French soldiers without which Wellington believed they would have lost the battle. His brother would later die that day.

Another Irishman Captain Edward Kelly from Co Laois became known as Waterloo Kelly after the removed the epaulettes of a French officer.The most famous Irish casualty was Major General William Ponsonby, an Irish MP from Cork, who died during a cavalry charge on the French lines.

There were also Irish in Napoleon’s army including, bizarrely, according to one account, two brothers fighting on opposite sides.

Catholics, mostly Irish, were only allowed join the British armed forces following the Catholic Relief Act of 1778. Lt Col Harvey estimates that 40 per cent of the soldiers who fought with Wellington in the Peninsular War between 1807 and 1814 were Irish.

Lieut Col Harvey’s book will be launched at Collins Barracks on Thursday at 10.30am as part of events to mark the 200th anniversary of the battle.

An exhibition on the Duke of Wellington will be opened at the Phoenix Park visitor centre in the afternoon and a memorial service for the fallen of all nations at Waterloo will take place at St Patrick’s Cathedral at 5.30pm on Thursday evening.

On Thursday afternoon Glasnevin Cemetery will host a unveiling of testored headstone plaques along with a tour at the graves of Waterloo veterans Lieutenant Henry Quill, Lieutenant Theobald Butler, Captain Benjamin Walker Nicholson and Lieutenant William Talbot.