The Supreme Court of Canada says employers must have just cause for firing a federally regulated worker who lacks union protection.

In a ruling today, the high court says dismissing such an employee without cause is unjust, and therefore not allowed under the Canada Labour Code.

The Canadian Labour Congress is hailing the decision as a win for all federally regulated employees, particularly half a million non-union workers at banks, telecommunications firms, transportation companies and some Crown corporations.

The Supreme Court ruled in favour of Joseph Wilson, who was dismissed without cause by Atomic Energy of Canada Ltd. in 2009 and given a severance package.

A labour adjudicator concluded that an employer could not resort to severance payments, however generous, to avoid a determination under the labour code about the dismissal.

Because the employer did not rely on any cause to fire Wilson, his complaint was allowed -- only to be later overturned in the courts, prompting the eventual appeal to the Supreme Court.