John Prescott has given his backing to one of the biggest building schemes approved on green belt land.
The decision to build 3,600 homes and businesses west of Stevenage, Herts, was welcomed by the council who say they have an acute housing shortage.
Tim Akeroyd, chairman of the Campaign Against Stevenage Expansion, said crossing the A1(M) to build will be an environmental disaster.
The A1(M) west of Stevenage has acted as a buffer to green belt development.
900 affordable homes
A public inquiry by the planning inspectorate looked at all the issues surrounding the building scheme.
The development will include 900 affordable homes, schools, community facilities, playing fields, shops and transport.
The deputy prime minister accepted a recommendation to approve scheme on Thursday but rejected proposals for an additional 5,000 new homes.
The leader of Stevenage Borough Council, Brian Hall, said: "We have worked extremely hard over the last 10 years to bring this development forward.
"There is a genuine housing shortage in Stevenage and we need to do something about it now.
"I am glad that the Secretary of State has recognised this and reached a common sense decision.
"Our work to regenerate and expand the town will have immense benefits for both our existing and future residents. "
Tim Akeroyd from CASE told the BBC that once you have crossed A1(M) motorway which has stopped development in its tracks then you have crossed the line for other development on the green belt to take place.
CASE say they have had 7,000 objections to the development of the area from residents in Stevenage and north Herts.