The Department of Transport's pounds 100m plans to upgrade the A303 from single to dual carriageway between Ilminster in Somerset and Honiton in Devon, 16 miles to the west, have raised fears that medieval field systems, wet woodlands and meadow havens for rare plants like the green-winged orchid will be irreparably damaged.
The DoT is pressing ahead with rebuilding and diverting the road only a year after another government department (Environment) designated the Blackdown Hills as an Area of Outstanding Natural Beauty (AONB).
Demands for the scheme to be scrapped have been made by a consortium of five green pressure groups, led by the Somerset Trust for Nature Conservation. They point out that 'improving' the A303 would be tantamount to building another motorway parallel with the M5 six miles to the north, and propose an alternative route, along the improved A358 link from Ilminster to the Taunton exit of the M5.
Mary-Rose Mangles, a Somerset county councillor, said: 'The whole thing is the most enormous waste of public money, a real misappropriation. For a government to AONB a medieval field system and then cover it with concrete and Tarmac doesn't make sense.
'It's not just the knock-on effect on the landscape. It's also on the Mendips quarries where they'll dig out tons of stone for building the road. Then there's the effect of intersections with lighting at night.'
Roger Martin, of the Somerset Trust for Nature Conservation, believes the DoT is determined to go through the Blackdowns simply because it seemed a good idea 30 years ago. 'Dualling from London to Exeter was the DoT's long-range programme long before the motorways were built so there's a fair bureaucratic momentum behind the task,' he said.
'Here they're proposing not simply to dual parts of the existing road but also to blast off through great swathes of sensitive countryside to do the rest. DoT engineers like a challenge. There's a very major human desire on their part to keep designing big new road schemes.'
An air of uncertainty pervades the tranquil landscape. Many farmers are worried that major engineering works will upset the area's delicate water table and deprive them of the springs that are their only source of domestic water.
Bob and Mary Hedges love the view of the Blackdown Hills from their filling station and village shop in the scattered hamlet of Newcott, near Honiton. Two years from now their view could be very different. The Government's dual carriageway will bypass and isolate their section of the road, leaping across Sandpit Hill 200 yards away. The new route, possibly mounted on concrete stilts, will carry their trade bucketing along the Otter Valley at 80mph.
Like other campaigners, Mr Martin is critical of the DoT's piecemeal approach. A public inquiry, expected this summer, will consider objections to only half the proposed route, the 9.5-mile section from Marsh to Honiton (including part of the A30). The shorter, but environmentally more sensitive, section to Ilminster will be kept for later. The green group suspects the DoT's tactic is to strengthen its case for that run by getting the easier section approved first.
A DoT spokesman denied that the department was being guileful. 'We're very aware of the beauty and unusual geology of this area so we're taking time to get this right,' he said. 'This scheme has the full support of the local authorities concerned and we've carried out a full review in the knowledge that the area was about to be declared an AONB.
'We don't believe the A358 would relieve the existing A303 traffic. We've examined the idea carefully and feel our original approach is the correct one. The A303 is an important strategic route and that's why it's being improved.'