A previously unseen first-hand report on the death of Michael Collins has indicated that his killing occurred largely by chance.

It is believed to be the first contemporary account of the ambush at Béal na mBláth.

Despite speculation, the document also suggests Collins was not shot by one of his own officers.

A charismatic figure, Michael Collins was chief-of-staff of the Free State forces during the Civil War and regarded as a brilliant military strategist.

Several films and reconstructions have been made about the ambush that claimed his life. It happened in August 1922 when he was on a tour of his Cork constituency.

An internal IRA document, unseen up to now and written two days after the ambush, shows that the shooting happened somewhat by chance as most of the IRA party had withdrawn from Béal na mBláth having given up hope of Collins passing.

The document written to IRA chief of staff Liam Lynch is published in a new book on the IRA by Dr Brian Hanley.

Dr Hanley, lecturer in Modern History at St Patrick's College Drumcondra, said Collins should have been much better protected on the journey.

Dr Hanley said the document suggests that Collins was not killed by one of his senior officers or one of his own gunners.

For decades this first-hand report on Collins death was hidden in papers of the former IRA chief of staff, Moss Twomey. But those papers were donated to UCD about ten years ago.