Walking the Mardyke and the lost fens of Essex

The Mardyke is a small tributary of the Thames, draining the lowlands of southern Brentwood and Thurrock before joining the river at Purfleet. An enigmatic watercourse, I’ve only previously seen it at Purfleet, and from snatched glimpses while driving across the M25 / A13 interchange, my eye drawn to the floodplains below.

Purfleet

At the mouth of the Mardyke, a small, abandoned harbour leads to a set of sluice gates, which prevent the tides from pushing upstream. There has been a sluice here since at least 1760, to facilitate the draining and reclamation of the inland fens. Previously navigable, the Mardyke is now sealed to traffic.

A footpath follows the canalised Mardyke inland, as far as a recreation and play area. A footbridge across the river still carries narrow tramway tracks, a remnant of Purfleet’s military history. The tramline ran from a large cordite magazine to the wharf and a lost pier. The echo of the storage magazine can still be seen when walking around Rainham Marshes nature reserve, where its earthen blast walls still stand.

Beyond the park, a quick detour to a trio of bridges gives a last glimpse of the Mardyke, before it heads into inaccessible territory. Note the WD logo on the older bridge, the letters separated by a stylised arrow. The WD stands for War Department, a government department with a long history in Purfleet, even if little now remains.

Tank Hill Road leads south, to Tank Lane, a narrow path which traces the high cliff top of an old chalk quarry. The gouged hillside now shelters a large housing development. Truck depots then lead to Botany Way, and the welcoming delights of Purfleet’s Arterial Road. A large ‘gentlemen’s club’ stands shoulder-to-shoulder with the Purfleet Car Wash.

Watt’s Wood

The road traces Watt’s Wood, the slopes littered with dumped mattresses, children’s toys and even a mobility scooter. The vibe isn’t great, but it’s the way to the river. Eventually, a footpath takes us into the woods. Lined on one side by tall, dark conifers, the littered path seems foreboding, yet it’s also well-trodden.

We leave the woods, and the path branches in three directions. Ignore the open, beckoning fields and pylons and push north along a narrow, overgrown path, towards the river.

On reaching the Mardyke the path opens up. As I arrived, a marsh harrier rose and wheeled away on strong, lazy wingbeats. Across the river, ponies grazed on rough pasture and grey smoke rose from a fire beside a Traveller site.

The river here is verdant, slow and clear. At Ship Lane, the path joins the road, and one has to walk a little way north to join the Mardyke Way, opposite the lane which leads to the Traveller site.

Floodplains and motorways

Along the next stretch, views of the Mardyke are largely lost, the river guarded by marsh and wet grazing land, hidden within its own, wide floodplain. In the background, the M25 sweeps towards its interchange with the A13, flanked by two slip roads.

The path takes us under the rumbling traffic, held overhead on pillars of steel and concrete.

The bridleway continues with rising woodland on one side, floodplain on the other, then passes under the A13. At Low Well Wood, a path leads up to and along one of the slip roads, but the landscape beyond is sadly off-limits. I could see two men fishing in a lake, so there must be a way in, somewhere.

Low Well Wood slopes down to the Mardyke, criss-crossed by myriad, well-worn paths. In late summer, the woodland was empty and silent, but seems well used, a place I’d have loved as a child.

Stifford Viaduct

Returning to the path, and approaching Stifford Viaduct, I found the track becoming more popular. This low but imposing viaduct opened in 1892 and makes a good place to stop. A footbridge, adorned with an eye-catching fish emblem, leads to Davy Down meadows, and there is finally a small riverside spot to rest beside the water. Along this walk I found access to the water difficult, with the riverbanks thickly vegetated.

A nearby information board claims the Mardyke has been running on its current course for over 30 million years, a far-fetched claim for what is essentially a large drainage ditch. I’ve also read claims that the Mardyke once joined with Kent’s River Darent as one river, now cut in two by the River Thames, shifted in its own bed by glacial ice sheets.

Leaving the viaduct, a good footpath leads along the southern edge of the river, with a cycle path on the north side.

The paths reunite and lead to a small roundabout, which one has to cross to take the path back down to the river.

The dyke stretches ahead like an old, disused canal, choked with sediment and growth, but rich in nature and lined by floodplain meadows. I suspect this landscape changes dramatically during winter flood.

A narrow bridge crosses the river, carrying a footpath which crosses the bridleway we’re following. We pass stables and then under Mederbridge Road, the Mardyke’s course shifting towards the north.

The lost fens

On maps, the river’s course now flows through landscapes described as fens, but in truth, the fens were drained and lost long ago. The river flows past endless acres of intensive arable farming, a desolate, scalped landscape of harvested wheat. At some stage, even the trees along this side of the Mardyke have been removed, although there is now some recovery.

“Until the late 19th century the Mardyke and its tributaries were wider than today and often navigable by boat. Shallow draught Thames barges would travel up the Mardyke and through the fens collecting corn and hay from farmers. The barges, often heavily laden with stacked bales, would be ‘poled’ through this flat landscape to take straw and hay to the large population of working horses in London. On the return trip, the barges would often bring the resultant manure, to fertilise the land.”

Land of the Fanns signage for the Mardyke Way

The river itself remains verdant, but there is a hard boundary between the channel and the heavily worked fields. With little shade next to the river, I walked out across the fields to sit beneath a single, stunted oak, a sole survivor of an ancient hedgerow.

Lower Thames Crossing

Moving on, at Orsett Fen, it seems even the fields of wheat may soon be lost. Carefully excavated pits have been sliced through the recently harvested land, preliminary work for the construction of the Lower Thames Crossing. If it goes ahead, this controversial, six lane trunk road will curve across the landscape, meeting with the M25 at North Ockendon.

As we walk on, the river is now little more than a reed-choked drainage ditch, a narrow ribbon of green, cutting through the dry, empty fields. However, even this slim slice of water attracts birdlife and dragonflies dance in the warm air.

After another footbridge, the channel splits, and the path turns east, towards a blocky, grey and white building. The path splits, both tracks following thin watercourses. The true path is the one to the left, heading towards a brick bridge, where another interpretation panel marks the ‘start’ of the Mardyke Way.

Detox centres and lost paths

Nearby, the Glass House Retreat is protected behind high, grey walls, a ‘detox and wellness’ centre which seems out of place in this old, low-lying landscape. A footpath continues behind the centre, but I found the way unclear. A wooden footbridge leads to a path, but the route was soon engulfed in thick nettles. A nearby gate also promised a path, but paddocks of electric fencing suggested no clear route.

With the path lost, I walked east along Fen Lane to pick up my next footpath. The lane makes for uneasy walking, the rough grass verges forcing one to tread the road, stepping up and aside when vehicles approach.

My destination was the railway station at West Horndon. The first footpath north was completely blocked by a field of weed-choked corn, but a more direct route can be found at Church Lane. Where the lane succumbs to rough track, footpath 142 heads west, then north towards the station, following yet another ditch.

On some maps this channel is marked as the Mardyke, but by now the river has split into many tributaries, and this watercourse was little more than a steep-sided trench.

Private lanes and friendly farmers

On reaching a private lane, I found the way ahead erased. A tractor was working this final field, tilling and turning the soil as the light faded. Walking across the broken stubble didn’t appeal, but the farmer took the trouble of stopping his work to ask if I was looking for the footpath. Having just ploughed it up, he said I was welcome to walk the verges of the field, if I didn’t mind the longer route.

Having made my way around the field, I almost missed the narrow stile leading up to St Marys Lane. This is another fast, narrow road, making for a dangerous but quick walk to West Horndon railway station.

As dusk fell across the empty, London-bound platform, a swaying, surly drunk entered the station and began muttering dire but mostly incomprehensible threats from across the dark tracks. He seemed very close to violence, but I figured he was too pissed to cross the footbridge and happily ignored him.

Waiting for the train, I could still hear and see the tractor working the dark field, the comforting lights visible through a broken treeline. A good ending to a long walk.