'Stealth' Route: Plan revives old journey to the West: Christian Wolmar and Nicholas Schoon look at the shift in government thinking in the face of a fierce 'green' campaign

'Damn right this will be another Twyford Down,' says the road protester David Plumstead. The Department of Transport is planning a new dual carriageway, starting at the M20 near the Channel tunnel terminal in Kent.

It will slice through the scarp face of the North Downs, running through a cutting more than 100ft deep - rather like the one made for the M3 at Twyford Down in Hampshire. Halfway down the steep, highly visible hillside it will emerge on to an embankment more than 50ft high before spanning, by a large bridge, the Royal Military Canal, built nearly two centuries ago.

The environmental damage this new 10-mile stretch of the A259 will do is impressive. It runs across the North Downs landscape which the Government designates as being of 'outstanding beauty' - it is a Site of Special Scientific Interest with rare burrowing wasps - and over a scheduled ancient monument.

Then, perched atop a low embankment, the road will sweep across the flatlands of the Romney Marsh by-passing Dymchurch, St Mary's Bay and New Romney. From the top of the downs and from the marsh, it will dominate the scenery for miles around.

The route for the new stretch - planned as three linked schemes - has been chosen, although public inquiries have yet to be held.

It will mark a new beginging for the Folkestone-to-Honiton trunk road, 230 miles of concrete and tarmac wiggling along the south coast to the West Country by way of the A259, the A27, the M27, the A31 and the A35 (see map, below). The Folkestone-to-Honiton route was given a statutory existence by the 1946 Trunk Roads Act - long before the advent of the motorways. Today, drivers making the journey from East Kent to the West Country speed across Kent on the M20, skirt around the capital on the M25 then head west on the M4 or M3.

But one day they might use this obscure long-distance highway. A series of 'strategic improvements' in the roads programme is turning most of this once slow road into fast dual carriageway. There are more than 20 separate schemes, several causing environmental damage in landscapes like the South Downs and the New Forest.

If the trend continues then 20 years on there will be a quasi-motorway linking the distant West Country to the big resorts and ports of the south coast and on to Dover and Folkestone, the Channel tunnel's entrance and the gateway to Europe. Protesters say the DTI is creating a 'stealth' motorway.

Most of these individual schemes en route are by-passes, relieving congestion in towns. Some are welcomed. The road widening and straightening schemes in the open countryside are justified as improvements needed to cope with existing traffic bottlenecks or to meet rising demand. For each scheme, the DTI will conduct a separate exercise in consulting the public, planning in detail and holding a public inquiry. But opponents say this conceals the big picture.

Protesters say linked improvements and by-passes are turning winding, single carriageway 'A' roads into cross country stretches of fast dual carriageway.

(Photograph and map omitted)