Dark River. That is one interpretation of Tamesa, the name (or something approaching it) by which this watercourse was known to its ancient Celtic inhabitants, thereafter called Tamesis by the Romans, Temes by the medieval English, and Thames by the English of today.

The Thames is the longest River entirely in England, whose capital London it birthed and has shaped ever since. And yet, the origin of its name is among the most mysterious in the country. The above is one of numerous possibilities, but it seems perhaps the most fitting. The Thames is very much a dark river: in the obscurity of its name; in the muddiness of its waters; and in the heritage of questionable human deeds committed upon it. ‘And this also,’ says Marlow famously in Joseph Conrad’s Heart of Darkness, ‘has been one of the dark places of the Earth’.

The river itself cares little what people call it, still less weighs the validity of one name against another. It surely recognises that Thames is not its final, settled name, merely its latest in an ongoing story. Indeed, it got a new one just this year on account of the intrepid Ugandan explorer Milton Allimadi:

The Samuel Baker he references did the same thing in the other direction, travelling from London to what is now Uganda where he ignored local names for geographical features and changed them to colonial things like Lake Albert. There is always a politics to names, which from the perspective of the features themselves – the Thames (or Gulu) is some 40-50 million years old – is mere imagination.

But the water itself is real enough, as is the material relationship it has shared with the people of its watershed for as long as they have crawled upon its banks. It is not a simple relationship. It contains not only water and fish but swords and shields thrown in as sacrificial offerings, flint tools and arrowheads, human and other bones, sewage, cholera, industrial effluents, dead bodies, state-of-the-art engineering and steamships stacked with a planet’s worth of colonial plunder. How many secrets must lurk in its darkness still…

It could be interesting to walk all the way along a river like that, couldn’t it?

This series follows an attempt to walk up the Thames and see how far we can go. It might have made sense to begin at its mouth, but its estuarine territory – the Thames Gateway, they call it these days – appears a land of industrial dereliction and crumbling infrastructure not designed for friendliness to walkers and in places dangerous or impassable.

So instead let’s begin near the border with Kent, where the river punches clear of the English capital and rampages on to the sea. The journey opens, then, on the bleak lower reaches outside the city limits. Here, as the warehouses rust and the silos stand empty, the ancient marshes creep round the edges, through the cracks, and know that this was always their land.     

Start:Erith (nearest station: Erith)

End:Thames Barrier (nearest station: Charlton)

Length: 12.8km (8 miles)

Region: Greater London – Borough of Bexley, Royal Borough of Greenwich

Topics: Erith; Erith Marshes industries; Crossness sewage treatment works; Thamesmead; Princess Alice disaster; Woolwich Arsenal; the Thames Barrier

(CORRECTION: ‘BARKING REACH’ should be slightly west of where it is on this map; where it is now should in fact be labelled ‘HALFWAY REACH’.)

Often the English spell their place names completely different to how they are pronounced, with one providing not a clue as to the other. Erith, on the Thames’s south bank at the edge of Greater London, is a case in point. It is not E as in estuary, nor even Eas in eel, but E as in ear. Ear-ith. Don’t ask.

The fossilised remains of a five-thousand-year-old forest have been found on the shores here, but so too signs that humans were here since before recorded history. The name’s origins are clearer than its phonetic misadventures: a hȳth is a landing place in the Old English language of the Anglo-Saxon immigrants, while ēaris not the organ that humans use less than their mouths but rather mud or gravel. A muddy or gravelly landing place: it was surely the river that brought them here, with this likely a convenient site for berthing ships in this area.

The river at Erith. It remains muddy, but since the discontinuation of the Pilgrim Ferry (which ran from the twelfth to the nineteenth centuries) only the sea birds really land here now. The massive landfill site on the Rainham Marshes – yes, those green and pleasant sunlit uplands – dominates the north side.

The village got its day in the sun, proverbially if not literally (this is England), when Henry VIII installed a naval dockyard at Woolwich to build his monstrous flagship Henry-Grace-à-Dieu, which in 1515 lurched down to Erith to be fitted out but probably never managed to kill anyone. By the Victorian period Erith had grown into a popular riverside resort, supported by the surrounding engineering concerns that serviced the lower Thames’s heavy industries and the Woolwich Arsenal. Thereafter its story is one familiar in this kingdom: crumbling decline, Brutalist apartment blocks, and endless visions of ‘regeneration’ with all the baggage of social cleansing and dismal shopping centres that entails.

To its charm, Erith does retain a few buildings from an era when English architecture valued character.

The old Town Hall, built in the 1930s.

Erith high street. It has a theatre, and the small red building in the middle is the old police station. That’s probably more than most English high streets have left by now. All the shops and other things have been gobbled up by the heaving Riverside Shopping Centre nearby.

Apart from residents, most people who know Erith’s name these days will likely be those coming to embark on one of the two long-distance walking trails that start here: the Thames Path (that's us), and the London LOOP.

So Captain Marlow continues in Heart of Darkness. The truth is probably not far distant. All this was marshland – dense, malarial, unworkable, uncompromising – and the river leaves you in no doubt here that it remembers it. As utterly as the industrial revolution transformed these lower reaches, leave it for a few years and all this will surely sink straight back into the mud.

Much of England’s present Brexit distress arose out of terrible short-term decisions, not least the Cameron Referendum in 2016. But it also cannot be understood outside the influence of particular national phenomena on a far longer scale. This country’s heritage of racism, or at the very least of English or British exceptionalism, is an obvious one, but another of equal stature is its violent decline, after two to three hundred years, as the first industrialised society on Earth.

In London a great deal of that industry was focused east of the city centre, amidst the appalling slums in which they kept the oppressed and impoverished workers who made it work. Access to the river, and with it the worldwide trading and looting networks of the British Empire, drew a great deal of this production and transport to its banks. But after World War II, with the rise of new industrial capitalist powers like the United States and Japan – and now especially China and India – British manufacturing lost its competitive edge. Many sectors which had served as the pillars of the industrial empire, such as mining and docking, were famously and brutally plastered into their deathbeds by the free-market revolution of Margaret Thatcher in the 1980s. The English economy lurched into its present undeath, grounded no longer upon making stuff but rather on imaginary chimeras such as finance and the ‘service sector’, whose benefit to society was always in question and since the financial crisis of 2007-8 has looked downright mendacious. As these elevated sectors rocketed away with the nation’s wealth, entire communities fell into deprivation, a sense of meaninglessness, and a need for someone to blame. England, with a long inheritance of beliefs that arrange the world’s peoples into a hierarchy with themselves at the top, likes to blame foreigners. Hence, perhaps, Brexit.

This is an overarching story whose effects are visible on almost any English landscape. On the Thames it will become toweringly blatant as we approach those primary beneficiaries in London proper, but out here on the Erith marshes it is already in plain view. The clutches of works that sprawl upon them are the not the roaring heart but the wheezing residues of erstwhile industrial power.

An asphalt plant, with a conveyor carrying in raw materials loaded upon its pier. The English still use roads after all.

Many of these conveyors line the stretch of river ahead, feeding these processing facilities with raw materials.

More numerous still are the fossils of industry gone by. Where a fair few of these jetties still service active berths and conveyor belts, many more are in ruin, sealed off with ‘DANGEROUS STRUCTURE’ signs to ward off the curious as they degenerate into the muddy waters. Others have altogether vanished, leaving only rotted stumps or splintered supports as evidence that they once existed. Every such structure has its story to tell of hard works gone by, if only we could hear them.

A disused dock in Erith, now no more than a water feature for new housing developments.

More new riverside properties look out over these ruined jetties, where a rusting crane once moved stuff around on them. What cargoes once graced these shores?