A waterway said to have been cut by the Viking Canute (also spelled Cnut) in the 11th century, the canal, according to the story, was constructed so his fleet of ships – blocked by London Bridge – could get upstream.

The story goes that in May, 1016, the Dane Canute (and future King of England), led an army of invasion into England to reclaim the throne his father, Sweyn Forkbeard, had first won three years earlier.

Canute needed to get his ships upriver of London Bridge to besiege the city which was held by the Saxons under Edmund Ironside (made king in April after his father Athelred’s death) but was blocked by the fortified, although then wooden, London Bridge.

So Canute gave orders for the digging of a trench or canal across some part of Southwark so his ships could pass into the river to the west of the bridge and he could encircle the city.

The canal – also known as ‘Canute’s Trench’ – was duly dug and the city was besieged – although the Vikings lifted the siege without taking the city (which does seems like a lot of work for not much result in the end) and the war was eventually decided elsewhere.

Various routes of the canal have been posited as possibilities – including the suggestion that there was an entry at Rotherhithe (Greenland Dock has been sited as one location) and exit somewhere near Lambeth or further south at Vauxhall (and one possibility is that Canute, rather than digging a long canal, simply cut through the bank holding back the Thames on either side of London Bridge and flooded the lands behind).

Various waterways have also been identified with it including the River Neckinger, parts of which survive, and the now lost stream known as the Tigris.

Whether the canal actually existed – and what form it took – remains a matter of some debate (although the low-lying, marshy land of Southwark at the time surely would have helped with any such project). But whether lost or simply mythical, the truth of ‘Canute’s Canal’ remains something of a mystery. For the moment at least.