The approval of a plan to build a new estate of almost 2,000 new homes next to Bletchley could be taken to a judicial review by furious city councillors.
The Salden Chase application was last week given the green light by Aylesbury Vale District Council, despite massive opposition from the people of Milton Keynes.
The controversial proposal had already received the thumbs down from MK Council, five neighbouring parish councils, Bletchley Town Council and city MP Iain Stewart.
But councillors in Aylesbury Vale, within whose boundaries most of the site falls, gave their approval – then delegated responsibility to their council’s officers to sort out the details.
Tory leader Andrew Geary has urged MK Council to consider whether it would be viable to launch a judicial review in a bid to overturn the decision.
Council leader Pete Marland, backed by his Cabinet, has now agreed to seek advice from the legal department on the viability of such action.
All the protesters say the new development could have serious implications for Milton Keynes.
They believe infrastructure proposals are insufficient, and traffic from the 1,855 homes would cause problems on roads in Bletchley, Newton Longville south west Milton Keynes.
They also believe GP services would be under pressure, as would the already-stretched MK hospital, and the burden on waste and recycling facilities would be too great.
Edith Bald said: “On the evidence presented to the meeting, we were certain this would be refused.”