According to the group, the cost of final salary pension provision has continued to increase at such a rate that Trinity can no longer afford to provide the benefits.

The consultation into the scheme's closure will run until 8 January 2010. If the decision goes ahead, members' existing pensions will stop on 1 April 2010 and they will accrue inflation after that.

If members choose to move to Trinity's other pension scheme, they will begin on a current salary.

A statement from the company stated: "Closing these schemes to future accrual would help limit the increase in liabilities in the defined benefit pension schemes and help the group to fulfil its commitment to eliminate the current deficit.

"Current contributing members, who would no longer build up future benefits in their defined benefit scheme, would be given the choice of building up future pension benefits in the existing defined contribution Trinity Mirror Pension Plan."

Unite has reacted with surprise at the announcement, claiming that some of its members are "very unhappy".

According to national officer Steve Sibbald, at recent meetings between Unite, the National Union of Journalists (NUJ) and Trinity, no indication was given that the changes would be put forward.

"They must have been thinking about this for quite a while because our members got a glossy brochure and a DVD explaining, in detail, what this meant for them," he said.

"The instinctive response would be to give Trinity a slap in the face. Our members will want to reply and I would be very surprised if the NUJ members did not respond in some way."