Brian Myerson, manager of UK Active Fund, which controls 11 per cent of Greycoat, welcomed the decision by investors at an extraordinary meeting to adjourn for three weeks a vote on the possible liquidation of Greycoat's assets.
"The [Greycoat] board will be forced to sit down and look at the Moorfield proposals," he said after the meeting.
Earlier this week, Greycoat rejected a pounds 200m all-share takeover approach from Moorfield, a property group less than a quarter of its size.
Mr Myerson, a former Greycoat director, said he was delighted shareholders had voted to adjourn his original proposal to sell off the company's assets.
He said Moorfield's proposals, which have so far been rejected by Greycoat as being too vague, had the backing of holders of 40 per cent of Greycoat's investors.
These are thought to include leading institutional investors such as Schroders and Newton.
Mr Myerson said these shareholders had already seen Moorfield's 40-page document and expressed their support for it, adding that he was "supportive" of both the proposals and of the Moorfield management.
Greycoat put a brave face on the outcome. "We have yet to see any detailed proposals from Moorfield.
"All we have had is one page of vague bullet points," said a spokesman.
Greycoat also reiterated its attack on Moorfield's offer, arguing the bidder had no experience of prime central London office properties and the offer contained no cash alternative.
Moorfield is run by Marc Gilbard and Graham Stanley, two former property analysts at US investment bank Goldman Sachs.
It plans to combine with Greycoat and then split the enlarged group into two separate companies, one based at London's Embankment Place and Buckingham Palace Road, together with their debts, and the other holding the remainder of the debts and assets of the enlarged group.
Shares in Greycoat, as high as pounds 25 at the end of the Eighties, closed a penny higher at 156p.Reuse content