IT sounds like a trick question - how can Bournemouth expand by a quarter without getting any bigger?

The town currently has 72,000 homes and most people would say it feels pretty full.

But an extra 18,000 new properties are needed in the next 20 years and a quick scan of a map reveals the problem facing planners - where will they go?

Councillors have vowed to fight tooth and nail to prevent any expansion northwards into the town's narrow strip of green belt and the existence of the sea rules out the south.

Unlike Poole, Bournemouth has no massive regeneration schemes in the pipeline that could produce hundreds of new homes at one stroke.

And the fact the town is flanked closely by Poole and Christchurch leaves just one option - a massive in-filling exercise.

Chris Husson-Martin, head of residential development for Knight Frank southern region, said developers were already working on that assumption and were becoming more and more inventive in their search for spare land.

This could lead to more and more office conversions, back garden developments and flats being built on hotel plots.

Leafy roads full of large detached dwellings - like those in Talbot Woods, Queens Park and Southbourne -- could also be prime targets for conversion into flats.

Mr Husson-Martin said: "The main areas I know developers are looking at at the moment are office buildings which are not being fully utilised and hotel sites. People are desperate to build in Bournemouth but are having difficulties finding suitable sites."

He said Boscombe was popular because of its suitability for high-density development and added: "At the end of the day, it's down to the town council.

"They can protect all the areas they want to protect but they also have a duty to the people of Bournemouth to be able to find these new homes."

The pressure of development is nothing new in Bournemouth. More than 1,000 new homes per year are already being built in the town so a further 18,000 over 20 years should not prove too difficult.

Phil Robinson, planning policy, conservation and design manager at Bournemouth council, said the real challenge was building the extra homes while protecting the town's existing environment.

"It's really going to be a case of more of the same," he said. "Two years ago, we completed 1,300 new dwellings in the borough and last year, we did 1,100.

"You think 'This can't carry on forever' but then somebody manages to find a new piece of land. Certainly, if you look at the planning applications we are receiving, there are lots of people seeking to build 15 or 20 flats.

"We have very few big sites. We've got Boscombe Spa and Terrace Mount but they are on a much smaller scale than Poole's regeneration sites.

"So instead, what we will see is a continuation of these kinds of developments - conversions, redevelopments etc - scattered throughout the borough.

"But we've got to make sure that we don't ruin the environment that we've got here. We can always cram in a few more houses but we don't want to ruin what is really a lovely town at the moment."

It's this issue that is concerning so many. While there may be the land available to accommodate an extra 36,000 people, can our already congested roads cope with their cars? Are there enough jobs for everyone, is there enough room in our schools to teach their children and are there enough shops to cater for the population boom?

Independent Cllr Ron Whittaker, who represents Throop and Muscliff, said Castle Lane had already "reached gridlock" and desperately needed investment.

"Any development must be supported by all necessary infrastructure costs up front," he said.

"But we all know that our region is not going to get large allocations of government funding to support all the necessary infrastructure costs to allow any reasonable scale of new development.

"This government is forcing through high-density development with no amenity space and little or no parking. None of us are happy about it but this is what we have to work to."

And David Crawford, deputy chair of Bournemouth Civic Society, queried what would happen if the town ended up with a surplus of housing that first-time buyers could not afford.

"This could turn out to be an extremely expensive guess if we end up with empty properties in 20 years' time," he warned.

"The only place these new homes can go is in the place of buildings that already exist. We could soon see instances when blocks of flats are replaced by bigger blocks of flats.

"It's always regrettable when town planning turns into town cramming but all we can do as the Civic Society is try and make sure that the replacement buildings are well designed and fit well into the area."

First published: October 21