MPs and environmentalists last night condemned the region's "unelected" regional assembly after it voted through massive housing plans that could change the East of England forever.

MPs and environmentalists last night condemned the region's "unelected" regional assembly after it voted through massive housing plans that could change the East of England forever.

Members of the East of England Region Assembly voted yesterday in favour of plans for 478,000 new homes to be built by 2021. They include 58,600 in Suffolk and 123,400 for Essex.

At a meeting in Southend-on-Sea, around 100 delegates from councils and other public bodies in the East approved government proposals which many fear could end up sparking an urban sprawl in the region.

In its historic decision, the assembly also decided to leave open the door for a brand new town along the lines of Milton Keynes.

However, they strongly opposed the idea of a second runway at Stansted Airport and rejected a government request to build an extra 18,000 homes which it thought was needed on top of the approved allocation.

A last minute proposal by Hertfordshire and Essex to reduce their allocations was blocked by members from Suffolk, Cambridgeshire, Norfolk and Bedfordshire.

The newly approved plans will now go to a period of public consultation starting on December 8 with final approval during 2006.

During an occasionally fraught two-and-a-half hour debate, members were told the "sustainable" proposals would secure the economic wellbeing of the region. Extra homes were needed to accommodate 379,000 new jobs, delegates heard.

Of the 478,000 homes earmarked for the six counties 60,000 have already been built and a further 210,000 are in the planning pipeline process.

Sue Sida-Lockett, chair of the assembly and who is from Suffolk, said: "This is a momentous day.

"This plan is aimed to improve the quality of life for everyone who lives in, works in or visit the region."

However, a string of councillors from authorities in Essex and Suffolk raised serious concerns mainly about transport and infrastructure issues.

Suffolk county councillor Kathy Pollard called for improved safety measures on the A14 to cope with the "undoubted heavier HGV traffic".

St Edmundsbury borough councillor Jeremy Farthing said: "The Deputy Prime Minister is playing a dangerous game of brinkmanship. Our infrastructure is pitiful."

Essex County council planning chief Peter Martin, said the proposals had been "a rushed job".

Earlier, delegates also voted in favour of grand economic vision for the region, which they claimed was one of the most prosperous in Europe.

Speaking after the meeting, David Simmons, spokesman for the Campaign to Protect Rural Essex, said: "Although there has been a compromise decision today it is still bad news. There is a lack of faith in these regional assemblies and it shows people are upset that their democratically elected councillors are ignored.

"In providing for all these homes the big issue is water – it is a strange issue where there will be a shortage of drinking water while other houses will be more at risk by being built on the flood plains."

The campaign's next step, he said, would be to encourage people to make their voices heard during the consultation period so more notice would be taken of the environmental concerns.

Conservative MP for Chelmsford West Simon Burns described EERA's decision as "environmental vandalism".

He added the assembly was an illegitimate body because it was totally unelected and directly answerable to no-one.

Fellow Tory MP Bernard Jenkin, who represents North Essex, added: "We do not have the transport infrastructure or the water supplies to deal with a huge number of homes in our part of Essex and there's a real problem with a system where someone at Whitehall knows better than people in Essex and that's why the assembly should go."

Colchester Liberal Democrat MP Bob Russell said: "This is an extremely difficult problem because we have a housing crisis in many parts of the country, not least Colchester. While lots of houses are being built within Colchester there are lots of people who can't afford the cheapest houses around and there is a dearth of rented accommodation in the public sector.

"What we need is to look at what the housing demand is for those who are in need of better houses, to concentrate on meeting their needs rather than the speculative needs of high priced housing developers."

Wil Gibson, chief executive of rural campaign organisation Suffolk Acre, said: "I think most of the housing developments are going to be in growth areas in the south of the region in Harlow and along the M11 corridor.

"A lot of the growth is to do with the London factor so the eastern region is providing the homes that ought to be provided in London.

"As a major city, London is one of the lowest density cities in the world. It's not catering for the people it can cater for."

West Suffolk MP Richard Spring said: "I greet the prospect of this housing with real alarm. There are really huge questions about that impact this is going to have on the quality of life in the East of England. Huge pressures on our road systems and our water table."