Simon Calder gets on his bike for an enlightening journey through the heart of Constable Country

Leading lights: that was how the High Lighthouse and the Low Lighthouse in Harwich were seen. When the two beacons appeared in line, they showed the course to steer from the North Sea to the harbour. But as the estuary of the Stour silted up, they could no longer be relied upon and became known as the misleading lights.

In these days of radar and global positioning, the lights are decorative. Yet for this journey they are symbolic. They signal the start of a bicycle ride through the artistic Anglian countryside - and welcome thousands of cyclists from the Continent.

Engeland's fietsland may look like a spelling error, but in fact the slogan invites Europe's keenest cyclists - the Dutch - to explore the countryside. They, plus Germans and Scandinavians, arrive to find an intensity of history as well as scenery. Not just any old history, mind: some of the story of art is written along the valley of the Stour.

The High Lighthouse remains a landmark for mariners, and now additionally for hikers. My attention, though, is on the Low Lighthouse. Besides housing a maritime museum, it also features in a work by John Constable - whose artistic spirit is your guide through the landscape.

"Bicycle" is not always the answer to the question "What is the best way to see a place?", but more often than not it is. All the more so in a nation endowed with a network of country lanes.

As the 21st century is diverted along mightier highways, the cyclist has the run of these thoroughfares. I'm meandering along both the National Cycle Network's Route 51 from Harwich to Hull and the Witchfinder's Way - a 27-mile circuit named after Matthew Hopkins, or the Witchfinder General, the 17th-century seeker of sorcerers.

One fine thing about estuaries is that there is so much to look at. The way the land melts into water, for a start. The meeting of the river with the sea produces nuances in tone and texture of which an artist would be proud. For this masterpiece, of course, we must thank the sky.

Clear skies and gentle breezes provide ideal circumstances for cycling in England: at this time of year, the sun caresses rather than cooks. But as Constable recognised, an accumulation of cumulus can enhance a picture. Some photographers spend plenty of time and money on filters and digital manipulation. Yet no electronic image can compare with the reality of the eastward waft of these pillows of moisture, softening the lines of the land.

More prosaically, I am studying the place names passing by. Primrose Hill, Wrabness Hall, Jacques Bay and Mistley Heath lead me to Manningtree, where I temporarily reconnect with the 21st century. The main railway line between London, Ipswich and Norwich provides access to Constable's countryside even for those not blessed with a bicycle.

Here, where the Stour narrows to a modest river, the England of Constable begins to take shape. So, happily, does the Painters' Trail, an artistic cycle route that begins and ends its 69-mile meander here. If that distance does not tally with your notion of a good day out, fear not; I shall be taking a short-cut later in the day.

The river marks the border between Essex and Suffolk, and you cross it northwards soon after leaving Manningtree's station. John Constable was born at East Bergholt, to Golding and Ann Constable, and a plaque on what remains of the house testifies to the event. Another memorial, on Moss Cottage, announces the location for his studio. But before you reach either of these, the trail turns south to the heart of Dedham Vale.

This stretch of the Stour Valley is a serene, painterly vision: the river meanders through a patchwork of well-tended fields and woodland, beneath a broad sky. "An elegance hardly anywhere else to be found," wrote Constable of the spot.

The huddle of buildings at the foot of a dead end comprise prime Constable territory: Flatford Mill, Valley Farm and Willy Lott's Cottage, plus Bridge Cottage. The first three are leased to the Field Studies Council, but the last is run by the National Trust. The trust runs guided walking tours to the places where Constable painted. They expertly translate the landscape from the two dimensions of the past to the three dimensions of the present.

Intellectually invigorated, you can embark upon the next wayward stretch of the Painters' Trail. After East Bergholt, Four Sisters and Squirrels Hall you meet the superhighway of the National Cycle Network, Route 1, and share it for a mile or so. Then you wind up and down the valley of the Brett, a tributary of the Stour.

By now the going is getting steep, relatively speaking: these are the "well-cultivated uplands" of which Constable writes. You descend to Nayland, and turn west to follow the Stour further upstream.

For anyone who likes an opt-out clause, the crossroads just past Malting Farm is ideal. This is where the Painters' Trail meets itself coming back, after a loop up to Gainsborough country around Sudbury. If you prefer to concentrate on Constable, just turn south for the final stretch of the artistic ride.

The route takes you down to the river, then up to Wormingford. Constable would have been familiar with St Andrew's, the church that appears to have sprouted from the rich earth. Cousins of Constable are buried in the churchyard, as is the 20th-century landscape artist, John Nash RA - who was also an official war artist in both world wars. The church wears its history well: the tower, built by the Normans, contains Roman bricks, while the medieval nave was embellished by the Victorians.

Now going east, you pass through a pair of villages as picturesque as their names: Little Horkesley and Boxted each seek to outdo the other as the custodian of English tradition: thatched cottages, well-behaved hedges and verges, and the air of contentment that Constable evokes.

At Dalethorpe, you encounter the A12 once more, and follow it across the Stour for a brief encounter with Stratford St Mary, whose mill was painted by Constable in 1820. The painter was educated at my final stop, Dedham. It is a classic English village - half timbered, half not, well endowed with places to eat, drink, sleep and think.

From here you could return to Flatford Mill, and seek out Willy Lott's Cottage, which appears in The Hay Wain (1821). Even though you are probably weary, reflect that cycling across Dedham Vale on an end-of-summer's day is considerably easier than pushing a cart out of a mud-hole. And then finish your journey by walking the pathway to Manningtree, through the scenes that "made me a painter" according to our greatest landscape artist.

The Painters' Trail is the subject of an excellent map and guide, price £3.50, available from local bookshops or from the East of England Tourist Board (0870 225 4800; www.visiteastofengland.com).

Bridge Cottage: 01206 298 260, www.nationaltrust.org.uk; open 11am-3.30pm from Wednesday to Sunday until 21 December, and from 3 January until the end of February at weekends only.

Field Studies Council: 01206 298 283; www.field-studies-council.org/flatfordmill. Flatford Visitor Information Centre: 01206 299 460; flatfordvic@babergh.gov.uk.

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