The Supreme Court of Canada has set new rules for an accused's right to be tried within a reasonable time frame, in a decision that criticizes the country's legal system for a "culture of complacency" when it comes to delays in criminal trials.

Superior Court cases will now have up to 30 months to be completed, from the time the charge is laid to the conclusion of a trial. Provincial court trials should be completed within 18 months of charges being laid, but can be extended to 30 months if there is a preliminary inquiry.

Any delays beyond these time frames are "presumptively unreasonable" and violate the accused's charter right to be tried within a reasonable time, the decision said.

"A culture of complacency towards delay has emerged in the criminal justice system," reads the majority decision.

"This court has a role to play in changing courtroom culture and facilitating a more efficient justice system."

2 men waited too long, court finds

Friday's decision was sparked by two separate cases where the accused waited years to be tried.

The first case before the court was an appeal brought by Barrett Richard Jordan, who was convicted of selling cocaine and heroin in British Columbia. From the time Jordan was arrested in December of 2008 to his conviction in February of 2013, more than 49 months had passed.

In the second case, Kenneth Gavin Williamson waited nearly three years to be tried on charges related to sex offenses against a minor decades ago.

The Supreme Court agreed the Ontario man's delay was unreasonable and endorsed a lower court's stay of proceedings.

The majority wrote that "the system has lost its way" in allowing unreasonable delays in trials and that the old guidelines — known as Morin (after 1992 Supreme Court case that established them) — have been "interpreted to permit endless flexibility."

If the Supreme Court's new time frames are missed, the onus is on the Crown to argue that the delays were caused by exceptional circumstances that were either reasonably unforeseen or beyond the Crown's control — like a medical or family emergency.

5-4 decision on new deadlines

The test doesn't apply when delays are caused by the defence team.

The decision to stay the Jordan case was unanimous. But four judges dissented on the new framework outlined by the majority, warning that it could lead to thousands of stays of proceedings in criminal cases.

Justice Thomas Cromwell — writing for the minority — warned that the new guidelines were "not an appropriate approach to interpreting and applying" the charter right to a speedy trial.

Cromwell argued the new deadlines are too blunt an instrument and setting firm timelines for what constitutes unreasonable delay is best left to legislatures.