The beginning of the biggest shake-up of planning policy in decades is fast approaching as the Secretary of State prepares to rubber stamp a scheme that will see half a million new homes swallow up swathes of the South West by 2026.

As D-day looms, the 21 West Country towns that have been chosen to bear the brunt of the development are gearing up to take on one of their biggest challenges in modern history.

They are bracing themselves for a public backlash against the unstoppable Regional Spatial Strategy (RSS), a blueprint for how the West should develop, which critics fear could devastate rural areas and threaten the region's identity.

Despite the current poor housing climate and the huge drop in trade for builders nationwide, Government planners still believe thousands of homes need to be built in the West over the next 20 years and maintain that their economic models show the market will recover.

In the next two decades, they say an extra 750,000 people will have arrived and want to set up home. And the Government says unless drastic measures are taken, there will be nowhere for them to live. In response to this influx, at least 23,000 houses must be built every year for the next two decades and be matched by thousands of jobs to ensure that as people move to the area, the local economy can continue to thrive.

The scale of the development and the impact it will have on the region has caused concern in the areas that will have to accommodate hundreds of new housing estates.

The RSS was devised by local authorities, planners, economists, population experts, building firms and property developers with the aim of making provisions for the ever-increasing population of the region.

The South West has the highest rate of population increase in the country, with thousands of people choosing to migrate here, drawn to the area by its beautiful countryside, coastal resorts, comparatively low crime rates and quality of life.

Taunton Deane Borough Council is taking the lead in working with its communities to ensure residents are able to have an input into the final plans. Taunton Deane must build 21,800 new properties and planners and consultants have been busy trying to identify suitable sites.

The Somerset borough, combined with neighbouring Sedgemoor, is also hoping an 25,000 extra jobs will be created.

At least 18,000 new houses must be situated in Taunton itself – which means the town's residential accommodation must expand by 45 per cent. The other 3,800 houses must be slotted in at Wellington, Wiveliscombe, Bishops Lydeard and other outlying villagers.

Taunton Deane Council's Forward Planning Manager Ralph Willoughby-Foster said this week that while the scale of development may seem daunting, there was no escaping the RSS.

"There is no choice in this for us," he said.

"We have to do it and so does every other council and local authority because it comes from the Government.

"Anyone who says that if we fight this growth and it will go away is lying.

"What we can do is work together to make sure the local communities are fully involved in the plans and can have their say.

"There will have to be infrastructure to support the housing, which could mean improved roads, new schools, village halls, and this would be funded through the developers.

"We almost have a blank canvas here and we want the communities to help us and tell us what they want."

The council has yet to identify all the sites for development but two of the most significant have already been earmarked.

The suburban Comeytrowe area to the south of Taunton will have at least 3,000 new homes, while the village of Monkton Heathfield in the north will have to accommodate 4,000, which will quadruple the size of the settlement.

Taunton Deane Council's Norman Cavill, member for Monkton Heathfield, said there was concern among the residents.

He said: "Of course people are worried, they are bound to be. An extra 4,000 houses is not a huge amount, it's a massive amount, and will amount to four times more housing in the parish which includes Bathpool, West Monkton and Monkton Heathfield.

"What we are most concerned about is the infrastructure. We need assurances that the appropriate transport links and facilities are in place to cope with this level of development."

The council is preparing to launch a "Community Engagement" period in which representatives of parishes affected by the plans will meet council officials to discuss the future. A full public consultation will follow in the spring.

Mr Willoughby-Foster said: "This is something that is going to affect everyone, there will be development across Taunton Deane and we have to accept that.

"But we want that to lead to greater investment in the area, better job opportunities, better facilities and a good quality of life.

"It doesn't have to be a negative change."

Although migration plays a big part in the need for extra houses, family break-up, divorce, and a growing number of single people are also to blame for the increased housing demand, which paints a bleak social picture for the future of society across the South West.

The RSS says there are more single-occupancy homes than ever before across the West, which means the demand for housing is increasing.

Mr Willoughby-Foster said: "People are spreading out. With more people choosing to live alone, we will need more houses."

Secretary of State Hazel Blears has been considering the RSS during a 12-week consultation process, which comes to a close in October. She will publish her final report before the end of the year. The report will either uphold the existing strategy or could include changes that may mean even more new houses – possibly 25,000 a year – to be built from Truro to Swindon.