On Saturday, I went to the Constable exhibition at Petworth House.  Like the wonderful Turner exhibition which the National Trust staged there last year, we were treated to little seen landscapes by the artist while he was staying in West Sussex.

Constable is of course best known for paintings of his native Suffolk, most famously The Haywain.  But he loved his visits to Petworth and Arundel.

His charming drawings and watercolours of Petworth, Tillington, Fittleworth, Bignor Park, Houghton and Arundel are of interest to everyone.  But for those who especially love the local landscape, the South Downs and the valleys of the Rother and the Arun, they have a special significance.

Constable admired Arundel Castle, but wrote that "all here sinks into insignificance in comparison with the woods, and hills .... I never saw such beauty in natural landscape before."

He was painting 180 years ago, and it is remarkable that so much of this landscape has gone unspoilt since then.

Much of it now lies in the National Park, previously an Area of Outstanding Natural Beauty, and so rightly receives the highest level of landscape protection.

But this very protection, necessary as it is, means that development pressures on the countryside of West Sussex outside the Park are increased.

Much of this was built on in the last century, but with the advent of planning controls in the 1940s, we have since been able to maintain discreet villages and prevent suburbanisation.

Despite these restrictions, villages expanded, often with inadequate infrastructure.  Flooding because of inadequate drainage is one consequence.

Now we face new pressure for further development.  Recent flooding has caused at least one council - Arun - to think again about the sense of building a new town on an area that's been under water (between Barnham and Eastergate).

But there's another concern, which is protection of the countryside for its own sake.  We all understand the need for new homes, but there should be a 'brownfield first' policy and development must be sustainable.  Instead, too many developers are now trying to build first on greenfield sites.

Constable saw "heavenly scenery" in West Sussex.  It is still here, and we must protect it, not just for ourselves, but for future generations.

The 'Constable at Petworth' exhibition runs until 14 March, and you can buy tickets on the National Trust website.  It is well worth a visit.

Christopher N Howarth