13 February 1820: Leonard McNally, playwright, barrister, United Irishman and an Informer died on this day. He was born in Dublin in 1752, and became a barrister in England before returning home to practise at the Irish Bar. He was one of the original members of the Society of United Irishmen and came to and defended many of its members in the Courts. He turned informer in 1794 following the arrest of the French agent the Rev Jackson.  The general opinion is that his nerve snapped under threats during interrogation but the exact circumstances that led to his decision to become a tout remain unclear.

His play Robin Hood (1784) was playing in Dublin on the night in 1798 when Lord Edward Fitzgerald was captured on foot of information he had provided. During the Rising of 1798 and in 1803 he found himself in the bizarre situation of taking money both from revolutionary defendants before the Courts and from Dublin Castle for providing them with information that would compromise his clients. While some had their doubts, and indeed one ‘doubter’ sent him a snake in a parcel from America as a token of gratitude, his dark secret remained hidden until his death in 1820. Ironically he was given a Patriots funeral. It was only when his family demanded that his pension of £300  per annum be continued that his secret life as a traitor was exposed.

He died at 22 Harcourt-street Dublin, 13th February 1820, aged 68. Then only did his treachery appear. His heir claimed a continuance of a secret service pension of £300 a year, which his father had enjoyed since 1798. The Lord-Lieutenant demanded a detailed statement of the circumstances under which the agreement had been made; it was furnished after some hesitation, and the startling fact became generally known, not only that he had been in regular receipt of the pension claimed, but that during the state trials of 1798 and 1803, while he was receiving fees from the prisoners to defend them, he also accepted large sums from Government to betray the secrets of their defence. The Cornwallis Correspondence, Madden's Lives of the United Irishmen, and communications from Mr. FitzPatrick in Notes and Queries, 2nd Series, put all this beyond doubt.
A Compendium of Irish Biography: Richard Webb Dublin 1878
http://www.libraryireland.com/biography/index.php