Fears have been raised that further delays to a major Norfolk transport plan could scupper the proposals and �90m of government cash - as an MP called for the scheme to be the subject of a public inquiry.

Fears have been raised that further delays to a major Norfolk transport plan could scupper the proposals and �90m of government cash - as an MP called for the scheme to be the subject of a public inquiry.

Ministers were last night facing increasing pressure for a public inquiry into the so-called Postwick hub and plans to close slip roads off the A47 to the East of Norwich amid fears over its scale and the impact it will have on existing villages and communities.

The plans, which would see the expansion of the business park, doubling of the park and ride site, and reworking on the key A47 junction to form the first phase of the proposed Norwich northern distributor road (NDR), are seen as crucial to securing thousands of new homes and jobs, as well as the delivery the so-called joint core strategy for the greater Norwich area.

But there is huge opposition and mid Norfolk MP Keith Simpson has also added his voice to the concerns, calling on the government to hold a public inquiry on proposals to upgrade the A47 Postwick junction, which if successful could see the rest of the strategy collapse like a house of cards.

Mr Simpson said he had turned to the “nuclear option” of the public inquiry because of increasing exasperation within the community that the views of the public were being ignored.

But the leaders of the four councils supporting the scheme have written to transport secretary Lord Adonis warning him that any further delay could threaten the growth plans - which last year were backed by the promise of nearly �90m of government cash - �21m for the Postwick hub and �67.5m for the NDR.

In a sign that the growth issue could be a key issue locally in the forthcoming general election campaign, and the battle to win the new Broadland constituency, Mr Simpson has asked Lord Adonis and communities secretary John Denham to meet him and members of Postwick and Witton parish council.

It follows a similar call by the Green Party's candidate Susan Curran, while the Lib Dems, and their candidate Dan Roper, have also raised concerns about the growth planned in the district, which also includes the Rackheath eco-town.

Mr Simpson said: “There is a considerable amount of public concern ranging right up to outright hostility to any kind of development whatsoever.

“Like a lot of local communities now, there is this feeling that government, whether it's local or national just seems to go through the consultation and it's all going to go ahead.

“They have got to explain why they want to go ahead with the current plans, and why the objections of the local community are going to be turned down

“The nuclear option is a public inquiry and the thing about it is that you never know how it's going to turn out,” he added.

“What I am trying to do is flash up a red light to them. I'm an experienced enough MP to know when objections are being made by just a few people who are dead against something. But there is real concern around Postwick, it's a widespread concern in the community rather than just a few people. The sheer scale of it is alarming people.”

The Conservative MPs intervention, which pits him against three councils of his own colour, is likely to prove a further headache to Tory run Broadland District Council and Norfolk County Council, which both support the growth schemes.

And in a joint letter the leaders of the four councils supporting the plans, comprising the Greater Norwich Development Partnership (GNDP), urged the government not to agree to the public inquiry warning it was simply a delaying tactic on behalf of opponents to the NDR and the growth agenda.

“This junction is justified on its own merits and provides a practical solution to enable an expanded employment business park and the wider potential for at least 1600 houses, which with the junction construction, will immediately provide immediate construction employment,” the letter said. “Any delay would severely threaten progress.

“The construction team for the junction is ready to commence and a public inquiry will add unnecessary delay and cost to the project. In a financial environment of minimising project cost and maximising the potential for delivering growth, this project has proven its case through a rigorous examination already.

“To generate further delay is simply unacceptable and unnecessary.”

Denise Carlo, spokeswoman for the Norwich and Norfolk Transport Action group welcomed the public inquiry call and said she hoped all the growth plans will now be considered by inspectors when the joint core strategy, is looked at in its entirety in the autumn.

“Ministers will find it hard to resist an inquiry now that the sitting MP is calling for it,” she said. “It's absurd for the GNDP to write saying don't hold a public inquiry. They have backed themselves in to a corner because they have made all their growth plans completely dependent on getting the slip road closures.”