Or why my garden may be haunted by Vikings

London is a far more aquatic city than is commonly realised. It sits, of course, on the banks of the Thames, but there are many other rivers, now buried under its streets. The Fleet is probably the most famous, once a wide watercourse, now entirely covered over. There is also the Tyburn, the Walbrook, the Westbourne and many more, all now flowing in secret channels under the metropolis. South of the Thames too there are secret rivers, but they are perhaps less distinct for in times past this was a boggy marshland where watercourses would have changed quickly, channelling around temporary muddy islands. One such ‘river’ passes close to where I live.* Here near Elephant & Castle it was known as the Lock Stream and down-river it was called the Neckinger, but taken together it has been referred to as Cnut’s trench.

To understand why a watercourse in London would be named for a Viking, we must look back across a millennium to the very birth of this country. The story of the making of England does not begin, as many believe, in 1066. In fact, that is where the story ends. The Kingdom of England was the result of six centuries of warfare that followed the collapse of the Roman Empire. This was a time of warlords and heroes. Arthur of legend fought the Saxons who invaded, but his people were beaten into Wales, Cornwall and Scotland. Then centuries later came the saxon Offa of Mercia, the first King of the English, but his overlordship collapsed at his death. Still later there was Alfred the Great of Wessex, his son Edward the Elder, his daughter Aethelflead, Lady of Mercia, and grandson Aethelstan, who in 927 finally unified the Anglekin – the English Speakers – into one kingdom. Yet even this did not last for this was the time of the great Viking invasions, the Danes and Norsemen who sought to follow in the footsteps of the Celts, Romans and Saxons and take Britain for themselves.

Fifty years before the decisive Norman victory at Hastings, the war was being fought by the weak Saxon king Aethelread the Unready and his warlike son Edmund Ironside. Their opponent was the great Danish King Cnut the Great, who would go on to command the very tides of the sea.** Aethelread died in April 1016 and his son was elected king by the Witan, the English parliament of noblemen. He at this time was besieged by Cnut in London, but escaped his clutches and fled to raise troops in the West Country. Cnut sought to follow him, taking his Viking armies in longboats up the River Thames, but he was prevented from travelling inland by London Bridge, which Edmund had fortified as a barrier to his adversary’s invasion.

However, somehow Cnut persevered and later faced Edmund in a battle at Penselwood in Somerset. How he by-passed London is the subject of a curious legend. It tells that Cnut ordered that a channel be cut through the marshes of Bermondsey and Lambeth so that his ships could be dragged past London, leaving the Thames at the Earl’s Sluice stream in Rotherhithe and re-entering it at the mouth of the river Effra at Vauxhall. It sounds like a fanciful story, but for centuries it has been believed that the Neckinger is in fact the remnant of the trench dug by the great Danish King. Truth or fiction, there is certainly something rather wonderfully picturesque about a Viking fleet avoiding the English defences by sailing against all reason overland. The only disappointment is that it does not appear to have been foreseen by some great sage, and thus fulfilled no ancient prophesy, but perhaps that only lends the story credibility.

The question of whether or not this event actually occurred has not been decisively settled, however there is some patchy evidence in its favour. Firstly the approximately contemporaneous Anglo Saxon chronicle refers to the digging of a trench in order to pass London Bridge, and indeed the dragging of Viking ships over land. Furthermore, the historian William Maitland, writing at the end of the eighteenth century claimed that archaeological evidence of the trench was found in the building of Rotherhithe Dock in 1694, citing as evidence “great quantities of fascines of hazels, willows and brushwood, all pointing northward.” However it has also been pointed out that digging a four mile canal in a matter of days or weeks would have challenged even Victorian engineers, let alone an invading force who would have needed to carry out this massive task under the noses of their enemies.

A convincing interpretation of events is that Cnut did not need to dig a new trench for his fleet. A thousand years ago the marshes south of the Thames were so full of streams and creeks that they were more properly a collection of islands. A map has been produced which recreates London as it was at the time of the Norman conquest and according to it, there may well have been natural channels enough for Cnut to by-pass London. They may however have been difficult to navigate and it was standard practice for Vikings to drag their ships when waters were particularly shallow or narrow. This would have taken time and, given the proximity of the fortified bridge, and the burgh of Southwark, it is plausible that Cnut may have had a defensive trench dug so as to impede attacks on his fleet’s progress.

So Lock’s Stream and the Neckinger may not truly be a trench dug by a Viking, but there remains the possibility that they are the remnants of the waterways through which Cnut sailed his fleet to challenge Edmund Ironside for the English throne.

*In fact, depending on the map, it might pass under my garden!
**Not that they obeyed him of course, but still.


The Danish Attacks on London and Southwark in 1016 link

The Myth of Canute’s Canal in South London link

Chronicles of London Bridge link