Unions representing thousands of Post Office staff and managers have pulled out of an "engagement exercise" on the future of the organisation amid continuing disputes over jobs, branch closures and pensions.
The Communication Workers Union (CWU) and Unite have written to the Government saying that the exercise is an "expensive" political move to prepare the Post Office for mutualisation.
CWU members in Crown Post Offices have had 11 rounds of strikes against plans to franchise or close over 70 branches, and are also in dispute about pay and jobs.
Deputy general secretary Dave Ward said: "It's impossible for us to continue being involved in this engagement exercise when the company refuses to listen to the concerns of its own staff.
"Our members have taken an incredible 11 rounds of strike action in defence of their jobs, services and pay, yet the company has so far refused to budge, choosing instead to spend tens of thousands of pounds on sending managers out to try to cover strike days.
"The public engagement exercise is an expensive political exercise in preparation for mutualising the Post Office. We don't believe you can have a successful mutual organisation which refuses to listen to and engage with its staff on the core issues of jobs and services and we cannot be sincere in any continued activity until our dispute is resolved.
"We have been urging the resolution of this dispute for months and have many suggestions on how to make progress. In the meantime we will be encouraging our members not to take part in this engagement exercise."