A formal objection has been lodged against plans for an eco-town in Warwickshire.
Protesters carried placards opposing the eco-town plans
The Tory MP for Stratford-upon-Avon, John Maples, has written to Communities Secretary Hazel Blears over plans for the old Long Marston airfield.
He raised concerns that the proposals for 6,000 new homes would spoil the rural character of the area.
The government says it wants at least 10 eco-towns by 2020 and is deciding which proposed sites will go ahead.
The scheme is one of more than 50 similar projects across the UK aiming to create carbon-neutral communities.
About 200 demonstrators turned up near the proposed Long Marston site on Sunday, carrying placards opposing the scheme.
Protesters argue there has not been enough consultation and say the schemes will be an excuse for building houses in inappropriate places.
They fear the new homes will lead to congestion in their villages as the new home owners travel to work and take children to school.
Protests have also been held at a proposed site near Gotham, south Nottinghamshire, and opponents of schemes in south Derbyshire and Leicestershire have petitioned Downing Street.
A shortlist of proposed towns is expected to be announced later this month.