LONDON - Tens of thousands of British public sector workers are walking off the job to protest the government's proposed changes to pension plans.

Union leaders say some 400,000 civil servants, border, prison and other workers are picketing ahead of the controversial reforms.

Cabinet Office minister Francis Maude says the strike is futile and will not result in a reopening of talks on pensions.

The walkout Thursday is the third in the past six months over pension reforms.