Romeo Phillion's lawyers entered a not guilty plea Thursday for the man who spent 31 years in jail for a murder confession he later recanted.

The legal maneuver aimed to prevent the Crown from quietly withdrawing the charge after the Ontario Court of Appeal quashed Phillion's conviction in March and ordered a new trial for the 1967 stabbing death of Ottawa firefighter Leopold Roy.

Phillion, 69, wants to be fully acquitted after being the longest-incarcerated person to have a Canadian murder conviction overturned.

The Crown and Phillion's own lawyers have argued there would be little to gain by retrying Phillion because of the time elapsed.

The new trial was ordered because of evidence that went undisclosed to Phillion's defence.

The appeal court concluded that prosecutors at Phillion's original 1972 trial never told his lawyers that police had initially concluded he was far from the crime scene and unlikely to be the killer.

Police claimed they had later disproved his alibi, which meant the Crown had no duty to disclose the information.

Phillion found out that police had verified his alibi 25 years later when a parole officer provided the details in a brown envelope.

With files from The Canadian Press