Transport Secretary Alistair Darling has done a decent thing for Sussex by rejecting a series of so-called improvements for the A27 trunk road. Now he must follow it up by other action.

Anyone who knows the A27 realises it is a mess.

It is hopelessly overcrowded at many points including the Chichester bypass, the Arundel bypass, Worthing and several sections between Lewes and Polegate.

Against all expectations, Mr Darling turned down suggestions by the roads lobby to make this road a minor south coast motorway by approving half a dozen separate schemes.

Unlike many of his predecessors, and transport bosses come and go as often as Albion managers, he appears to have recognised the unique landscape of the South Downs which are likely to be awarded national park status even though the process is taking for ever.

It would be utterly incongruous to designate such a park and then ruin half of it with great gashes through the chalk so that drivers can complete journeys a few minutes faster.

You have only to look at the schemes that have already been completed to see how damaging they can be.

The Brighton bypass may have taken a lot of traffic out of the city centre but it has destroyed the peace and tranquility of nearly all the downland close to the built up area in a seven-mile stretch from Stanmer to Shoreham.

A widening scheme at Clapham in West Sussex near Worthing has transformed a pleasant rural part of the county into a motorway junction.

The Adur bridge is an affront to the eyeballs more than 30 years after it was built and the grass still has not grown back on the sides of the Lewes bypass after a similar length of time.

All the rejected schemes would have been damaging.

The Chichester bypass would only have been made even uglier by any changes. The hippies are already camped in Binsted woods near Arundel in the expectation that this devastating scheme would be approved.

Between Lewes and Polegate, any widening would spoil one of the loveliest and most sensitive landscapes in England while the impact of any schemes to bypass Worthing would obliterate prime sections of downland such as those near Cissbury Ring.

What now? Mr Darling has the option of doing almost nothing which would protect the landcape but result in increased congestion.

He could go in for road pricing which would cut congestion but which would be seen as unfair by many drivers. He could create new tunnels at places such as Worthing and charge tolls for them.

He could also spend some of the millions saved on these road schemes by investing in the underused Coastway railway lines.

These badly need improvements including more passing loops, reworking of the Ford junction and changing the layout at Brighton so that through trains can get through without blocking the London line.

The Polegate to Pevensey line needs reinstating so that trains do not all have to drag into Eastbourne and back.

The Hastings to Ashford line needs double tracking for its entire length and electrification. Nearly all the stations are in dire need of improvement.

There are far too many people packed into this crowded corner of a crowded country.

We cannot all use cars and there must be a good alternative.

Mr Darling's surprise announcement is the first step towards achieving that but there are many more still to take.