The Supreme Court of Canada has ruled a federal law passed in 2011 that retroactively abolished accelerated parole review for offenders who had already been sentenced violates a person's charter right to not be punished again.

Today's decision strikes down section 10(1) of the Abolition of Early Parole Act and means all those sentenced prior to March 28, 2011 may qualify for accelerated parole.

Justice Richard Wagner wrote that the law automatically extended the minimum period of incarceration without regard to individual circumstances.

The case involves Christopher John Whaling, a Vancouver arms dealer who was convicted of three gun offences in September 2010. He was sentenced to four and a half years in jail.

As a first-time, non-violent offender, Whaling became eligible for accelerated day parole, which allowed him to be released on parole after serving one-sixth of his sentence.

In March 2011, the federal government implemented a new law abolishing the accelerated day parole program, as well as having it retroactively apply to those sentenced before the new law was even passed.

As a result, normal parole provisions would apply instead to the offenders, which changed the timing for their eligibility.

Double jeopardy

That’s what happened to Whaling, as well as two other inmates Judith Lynn Slobbe and Cesar Maidana, who were serving sentences for serious but non-violent crimes.

Whaling’s parole was delayed by three months, Slobbe’s by nine months and Maidana’s by 21 months.

The three launched a constitutional challenge to the law, saying that it infringed their right guaranteed under section 11 (h) of the Charter of Rights and Freedoms, which states that a person found guilty and punished for an offence has the right not to be tried or punished for it again.

In other words, the charter protects against double jeopardy.

Whaling, Slobbe and Maidana won their case in the B.C. Court of Appeal and B.C. Supreme Court.

The federal government appealed the ruling to the Supreme Court.

Today, Canada’s highest court dismissed the federal government's appeal.

A spokesman from Public Safety Minister Steven Blaney’s office said the government is examining the impact of this decision.

“Our Conservative government has been clear,” Jason Tamming said in an email to CBC News. "We do not believe that white collar criminals and drug dealers should be released after a mere one sixth of their sentence."

Mobile users, read the ruling here