A Canadian intelligence officer who admitted Wednesday to spying for Russia told authorities he walked into the Russian Embassy in Ottawa in 2007 and willingly offered his services.

Sub-Lt. Jeffrey Paul Delisle, a 41-year-old intelligence officer with the Royal Canadian Navy, was in Halifax court where he pleaded guilty to a breach of trust charge and two counts of passing information to a foreign entity.

Delisle's lawyer, Mike Taylor, told reporters that he and Delisle agreed that pleading guilty was the right thing to do.

"It's not so much a matter of deciding whether or not he was guilty, it's determining whether or not this was the right step to take -- whether or not there was a good reason to go forward and defend the charges based on any options in terms of defences," Taylor said outside court Wednesday. "There's no good reason to simply put on a show for the public, to go through the motions, when in my estimation the outcome was clear. And Mr. Delisle was realistic about that and he didn't see there was any sense in dragging it out, wasting the resources of everyone involved, to simply go through the motions."

Taylor said that the information that was leaked never "jeopardized the lives or safety of any of the men and women operating with the Canadian Armed Forces."

According to previously unpublished material from a bail hearing in April, Delisle admitted to authorities he sold Canadian secrets to Russia for about $3,000 per delivery.

Using a thumb drive, he would download intelligence from a system called the Stone Ghost computer, which contains information from the U.S., Britain, Australia, New Zealand and Canada. He would then hide the drive somewhere on his body when leaving the secure area and later pass it over to the Russians.

This started in July 2007, shortly after he says he offered his services to try to help support his family, even as his marriage was falling apart.

"That was the end of my days as Jeff Delisle," he told authorities about walking into the Russian Embassy for the first time, according to the facts read out in court in April, which were under a publication ban until his guilty plea Wednesday.

"It was professional suicide," he said.

The transactions continued until 2011 while he worked out of Ottawa and Kingston, Ont., and Halifax and Bedford, N.S.

Things began to go awry when he travelled to Brazil to hand over intelligence to a Russian handler.

He returned with more money than usual, but either he or the Russians were worried that Canadian authorities might have been onto him.

There was talk of setting Delisle up in a safehouse in Austria, but that never happened because he was arrested in January 2012.

The Russian foreign ministry denied media reports that four staff members of its embassy in Ottawa were expelled from Canada over the alleged espionage operation.

Delisle has been in custody since he was arrested in January.

Breach of trust is a Criminal Code offence that can carry a five-year sentence. Passing information is a violation of the Security of Information Act that could net the disgraced officer life in prison.

By pleading guilty, Delisle gave up his right to a trial. The move came as a surprise because Delisle had previously requested to be tried by judge and jury. His lawyer, Mike Taylor, wasn't immediately available for comment.

Delisle is due back in court for a two-day sentencing hearing on Jan. 10, 2013.

-- With files from Allen Rollin

SPY CASE TIMELINE

1971: Jeffrey Paul Delisle is born.

January 1996 - Joins the reserves as an intelligence operator; conducts intelligence gathering operations.

May 3, 1997 - Marries Jennifer Lee Janes

Feb. 17, 1998 - Files for bankruptcy.

March 2001 - Enrols as a regular member of the Canadian Forces.

November 2006 - Promoted to sergeant.

2007 - Starts a stint at the strategic joint staff division in Ottawa. According to material from a bail hearing, Delisle walked into the Russian embassy in Ottawa one day and offers to sell intelligence secrets.

July 6, 2007 - According to the RCMP, Delisle begins downloading intelligence from a system called the Stone Ghost — a computer system that shares information from the “five eyes” (United States, Britain, Australia, New Zealand and Canada) - and handing it over on a thumb drive to Russian agents. He’s paid about $3,000 per exchange.

June 2008- Delisle and his wife sign a separation agreement, handing him much of the couple’s debt.

July 2008- Receives a commission, becomes a naval officer.

2009 - According to court documents, Russian contacts tell Delisle to meet his handler in Brazil. Shortly after his return, military begins investigation.

Aug. 2011 - Joins HMCS Trinity, an intelligence facility at the naval dockyard in Halifax that tracks vessels in Canadian waters. The centre is a multinational base with access to secret data from NATO countries.

Dec. 2011 - Delisle’s house is raided.

Jan. 14-15, 2012 - Delisle is arrested and charged with breach of trust and communicating safeguarded information to a foreign entity without lawful authority.

April 2012 - Facts of the case are read into court record during a bail hearing, with a publication ban in place.

Oct. 10, 2012 - In a surprise move, Delisle pleads guilty