The A30/303 dualling would go through the Blackdown Hills

The decision to delay the plan has led to fresh fears over the dualling of the A30 and A303.

Devon County Council says it believes it is the proposed improvements to the A303 which have caused the decision.

But a spokesman for the Office of the Deputy Prime Minister says the delay is to give more time to decide if further intervention is necessary.

We must hope and pray this is not an indication that ministers have already made up their minds Cllr Christine Channon

Exeter's business community has reacted angrily to the delay.

The Exeter Chamber of Commerce has accused the government of disjointed thinking "or something sinister" in overriding the decisions of the region's elected bodies.

Chairman Brian Thornton said: "If it's a blatant attempt at another delaying tactic, the government should be publicly exposed.

"If it's a case of un-joined up thinking, they should withdraw their objection. If it's a sop to the environmental lobby, they should be humiliated."

Devon County Council says it is seeking urgent clarification of the government's position.

Christine Channon, leader of the county council, said: "Directing us at the eleventh hour not to adopt the plan is puzzling to say the least, given that improvement of the A30/A303 is already included in the existing structure plan."

"We must hope and pray this is not an indication that ministers have already made up their minds."

Planning authorities in Devon and Cornwall and the South West Regional Development Agency have been campaigning for improvements for years.

The council says it is to seek urgent clarification from the government.

The A30/303 dualling scheme through the Blackdown Hills which is a designated Area of Outstanding Natural Beauty (AONB) is seen as vital by businesses in Devon and Cornwall, but has sparked strong opposition from environmentalists.

Businesses in Somerset say they would also prefer the dualling of the A358 up to Taunton where it joins the M5.