A £50m upgrade of road, rail and bus routes is linked to Norfolk's planned eco-town.Although the £9bn project at the former RAF Coltishall base strives to provide thousands of jobs on site to cut down travel-to-work pollution, there will still be the need for some commuting to Norwich.

A £50m upgrade of road, rail and bus routes is linked to Norfolk's planned eco-town.

Although the £9bn project at the former RAF Coltishall base strives to provide thousands of jobs on site to cut down travel-to-work pollution, there will still be the need for some commuting to Norwich.

So backers are seeking to bolster transport connections with the city - and hoping the government, which is keen to promote such eco-towns, will help pay for them.

Ideas include a new link round bypassing Coltishall to the west, and an upgraded B1151 road connecting with the planned Norwich northern bypass.

A new rail link could involve using part of the Bure Valley Railway tourist line, and there are plans for a bus priority route via Hainford and the A140.

Developer Richard Davies, whose consortium is behind the eco town bid, said the transport links would cost £50m, which roughly matched the value of the site. He hoped the government would provide help and incentives towards the funding, and was currently in negotiations.

“Without these transport links the eco-town doesn't make sense. They are an essential part of the scheme.”

But developers could not afford to bare the full cost, along with having to spend another £30,000-plus on each home to provide zero carbon housing - and needed the government to help.

The Coltishall scheme has reached a shortlist of 15 vying to be in the final 10 sustainable communities on prime minister Gordon Brown's wish list.

After being chosen from 57 hopefuls Mr Davies said the Norfolk one was less contentious than some others, and had a chance of knocking some of the remaining contenders “out of the arena” if there was a political will in the county.

Ed Hanson of scheme agents Barton Willmore said the project aimed to provide 3,000 jobs, including special live-work units enabling people to stay on site for their business.

But with 10,000 homes planned, it would be “stupid” say people would not commute to Norwich.

The rail link, which shows a new station near the southern end of the old air base runway, could link in with the current Bure Valley Railway - but did not depend on it - added Mr Davies.

He confirmed the railway had been alerted to the idea, but there had been no negotiations.

“It has been mooted and is an option, but we could put the rail link somewhere else,” he added.