In a national vote on which county’s landscape best embodies Englishness, every county would presumably vote for itself. But when the War Office commissioned Frank Newbould in 1942 to design a poster with the patriotic slogan ‘Your BRITAIN – fight for it now’, it featured Sussex, with a shepherd herding sheep in the foreground and Belle Tout lighthouse on the distant horizon.

In the ‘green and pleasant’ stakes, Sussex holds the advantage that the seeds of our alternative national anthem ‘Jerusalem’ were sown during William Blake’s stay from 1800 to 1803 in the coastal village of Felpham near Bognor Regis. But while it has prompted the occasional poem, Sussex has inspired more than its share of art. In fact, Cornwall’s claim to the title of most painted English county is currently being challenged in Pallant House’s exhibition Sussex Landscape: Chalk, Wood and Water – a show of 100 works by 60 artists that, unusually for a gallery specialising in modern art, opens with a Turner sketch of Chichester Canal, a study of Brighton beach by Constable and Blake’s wood engravings for Thornton’s ‘Pastorals of Virgil’ inspired by Felpham, his only taste of country life.

Unlike Newlyn and St Ives in Cornwall, Sussex boasts no Hastings or Eastbourne schools of artists, although the county did become a testing ground for avant-garde ideas when the Camden Town and Bloomsbury groups decamped there during the first world war to apply the lessons of French post-impressionism to the downland landscape. ‘Going modern and being British,’ as Paul Nash put it, was never easy and some efforts look a tad provincial, though Edward Wadsworth makes a good stab at cubism in his proto-vorticist ‘Landscape’ of 1913 (see below) and John Armstrong at surrealism in his dreamscape ‘Heaviness of Sleep’ (1938), envisioning the Seven Sisters in the distance. It probably helped that Armstrong was born in Hastings, just as the fact that Keith Vaughan hailed from Selsey would lend substance to his abstract ‘Coast Defences (Seaford, East Sussex)’ (c.1959-62).

Vaughan owned a converted railway carriage on Pagham Beach, and visiting artists improvised makeshift studios. Ethelbert White drove a horse-drawn gypsy caravan around the county in search of subjects; Ivon Hitchens parked one on a piece of woodland near Petworth, eventually replacing it with a bungalow he called Greenleaves. Eric Ravilious fixed up two Crimean War fever wagons as a bedroom and studio. Even artists who could afford to rent a farmhouse, like Vanessa Bell and Duncan Grant, were prepared to rough it. Charleston had no electricity, phone or boiler but for a conscientious objector it was better than the army, as Grant was reminded when the wind direction carried the sound of gunfire across the Channel.

Bell and Grant painted the garden pond, which Grant fantasised about stocking with flamingos; the waters of Nash’s ‘Tench Pond in a Gale’ (1921-22) were more troubled, painted in the year of his post-war breakdown. Lashed by wind and rain, the image feels furiously romantic beside the clean-cut modernism of Nash’s later ‘The Rye Marshes, East Sussex’ (1932), commissioned as a poster by Shell to tempt young metropolitans into their cars. Piper’s collaged ‘Beach and Starfish, Seven Sisters Cliff, Eastbourne’ (1933-4) has a surprisingly political message: turned upside-down the newsprint papering the cliff warns of the threats of socialism and Nazism lapping at our shores, while the nearby lighthouse flies a Union Flag.

Of the three elements in the show’s title wood gets the least attention, perhaps because the patchy woodland of the Weald no longer lives up to its Saxon meaning of forest. Ethelbert White captured its old-fashioned charm in ‘Sussex Landscape’ (c.1930); never that bothered about going modern, he operated on the democratic principle that ‘when a picture pleases a tongue-tied farmhand… the artist has not gone wrong’. Contemporary furniture maker-turned-artist Wycliffe Stutchbury celebrates the beauty of weathered wood in ‘Gayles Farm 5’ (2020), an elegantly undulating screen tiled with chips of old fencing from Sussex fields, but the hero of this exhibition is chalk. For northerner Andy Goldsworthy, whose ‘Chalk Stones’ (2002) cross the final room, the white stuff came as a revelation – ‘to dig a hole in Sussex and find chalk, so absolutely pristine and pure and white… was like finding the sky in the ground’. Ravilious, brought up in Eastbourne, was nurtured on it. The view in his ‘Chalk Paths’ (1935) may be invented, but he was so at home in the downland landscape that his brush could feel its way over its bumps and hollows and follow its ancient tracks in imagination.

Sussex inspired a whole way of painting, Ravilious explained, ‘because the landscape was so lovely and the design so beautifully obvious’. Nothing models form better than wind and water or carves more elegant lines in hills than generations of sheep. Stand aside, Richard Long: sheep are the real land artists. When they make a line by walking, it lasts.