The Court of Appeal has ordered a retrial in the case of a 29-year-old man who was acquitted of murdering his mother by reason of insanity.

Paul Henry had pleaded not guilty to murdering his mother Ann Henry at their home in Abbeystown in Roscommon in September 2011.

He was found not guilty by reason of insanity by a jury and was sent to the Central Mental Hospital by Mr Justice Paul Carney on 7 May 2014.

Mr Henry had sought a retrial so he could plead and be convicted of manslaughter by reason of diminished responsibility.  

This would mean he would serve a determinative sentence rather than being under an indefinite regime at the Central Mental Hospital possibly for the rest of his life.

The Director of Public Prosecutions sought to have the insanity verdict upheld.

The Court of Appeal first determined that it had jurisdiction to consider the appeal because it is a Constitutional court in contrast to its predecessor.

The three-judge court went on to find that there was an "element of misdirection" by the trial judge to the jury.

Mr Justice George Birmingham, who sat with Mr Justice Garrett Sheehan and Mr Justice John Edwards, ordered a retrial.

The case for retrial will be listed in the Central Criminal Court in two weeks time, the court heard.