The Taoiseach is defending sending former Justice Minister Alan Shatter the terms of reference for a Commision of Investigation - before they were made public in the Dáil.

It has emerged overnight that in letters between the government and Mr Shatter last year that the terms of reference were sent to him a month before they were sent to the Dáil.

Mr Shatter had objected to the inquiry investigating his role, given that he was in litigation over the findings of the Guerin report.

But Enda Kenny says the government was making it clear to Deputy Shatter what would happen:

Last night the Department of the Taoiseach released letters from Alan Shatter - where the former minister tries to exclude himself from an investigation into alleged Garda malpractice.

In the letters, Alan Shatter's lawyers argued that it would be "gravely unconstitutional" for a Commission of Inquiry to investigate Alan Shatter's performance in office, when he is separately taking legal action against the Guerin report.

Shatter's lawyers went on to say Shatter expressed grave concerns that the Commission of Investigation into the Guerin Report would interfere with his High Court challenge to the same.

Brian Gallagher - a partner in Alan Shatter's own legal firm - said that the Commission of Investigation could not be separated from the findings of the Guerin Report, which reached wrong and "unconstitutional" conclusions.

The Department of the Taoiseach dismissed his concerns - saying the alleged Garda malpractice investigated by Guerin was important enough to merit a full Commission of Investigation.

Deputy Shatter himself then wrote to the Ceann Comhairle - demanding that the terms of reference be changed, saying they would otherwise be a "direct interference" in his High Court case against Guerin.

The Ceann Comhairle could not change those terms of reference - but did agree that no debate could be allowed, a decision that led to last week's walkout in the Dáil.