Jeffrey Delisle, the former Halifax naval officer who sold secrets to Russia, will not appeal his sentence.

He is serving 20 years in prison. He received credit for the 1½ years he spent in custody after his arrest.

Now, his lawyer, Mike Taylor, says his client will not appeal.

He said it would be difficult to convince an appeal court the judge made an error in law.

"It's not essentially another kick at the can. It's something where you have to point out a mistake has been made. I think the chances would be remote. Based on a number of discussions about those reasons, Mr. Delisle has instructed me he doesn't want to appeal," said Taylor.

Delisle was the first person to be sentenced under Canada's Security of Information Act.

He pleaded guilty last October to one count of breach of trust and two charges of passing information to a foreign entity that could harm Canada's interest.

Taylor had asked for a 12-year term for Delisle.

The former intelligence officer could start receiving unescorted day passes in just three years and he will be eligible for day parole in September 2018.