Business secretary Lord Mandelson claims that the only way for Royal Mail to “modernise” is to privatise it.
He is pushing through the Postal Services Bill to achieve this aim.
But the government can be forced to back off if there is action.
London postal workers were set to announce a ballot for industrial action as Socialist Worker went to press.
Management cost-cutting and job-slashing measures have triggered the dispute but the issues of privatisation and the attack on the company pension scheme are also causing bitterness.
Up to 10,000 workers will be balloted unit by unit and could be on strike by the end of May.