The pressure by institutional investors follows a complete breakdown in communications between Mr Montgomery and Victor Blank, the Mirror chairman, as the newspaper publisher's board considers two competing takeover approaches.
Some large shareholders in Mirror have indicated their support for Mr Blank in his battle with Mr Montgomery. They have also warned they are prepared to requisition an extraordinary general meeting to oust Mr Montgomery if necessary, although this is considered to be an extreme option.
The majority of Mirror's 12 directors are currently believed to support Mr Montgomery's stand. But one institution yesterday urged them to think again. "Ultimately I don't think they'll go through with [their support]," the shareholder said. "All of them have got jobs. Are they really going to go if David does?"
It is understood that Hermes, the pension fund management group, yesterday met Mr Montgomery and urged him to step down. Alistair Ross-Goobey, Hermes' chief executive, confirmed that the meeting had taken place but refused to say what was discussed. "I have nothing further to say on the matter," he said.
However, some fund managers believe that Mr Montgomery is preventing them from getting the best value for their shares by blocking a potential deal with Trinity, the regional newspaper publisher.
Regional Independent Media, the venture capital-backed group which publishes the Yorkshire Post, has tabled an indicative bid for Mirror which values the group at pounds 913m, or about 200p per share. Mirror's board rejected the offer, but RIM has indicated that it might be prepared to offer a higher price if it is allowed to carry out some due diligence on the company.
However, one shareholder yesterday expressed concern that the bidder was a highly leveraged group and that the Government might stop it from taking control of the Mirror titles, which have traditionally supported Labour.Reuse content