Canute's Canal
King Canute and the earliest London canal that never was?
The story of Canute's Canal that was supposedly built to by pass London Bridge in order to attack the City of London in 1016 is perhaps a myth and nothing more. There is much speculation about what form Canute's Canal took. Some arguments suggest that the land south of the Thames was low enough for ships to cross on very high tides, where others assume that existing ditches were used and deepened

'Canute's ditch' and the route it is envisaged to have taken
What ever the format was it certainly seems that Canute sent his ships across the land to the other side of the bridge. However the idea of his building a canal of perhaps four miles in length is somewhat incredulous especially when it couldn't have been done without the English peoples knowing. London Online suggests that "the statement that he dug a canal from Rotherhithe (then known as Retherith) to Battersea, as some writers would have us believe, and so diverted the course of the river, must be an exaggeration."

An early image of London Bridge. This is the stone version built in the 12th Century, some 160 years after King Canute's attempt
William Maitland and his research
Despite the apparent exaggeration, there is some minor evidence that a cut of sorts was built. Interviews conducted by William Maitland, a historian and biographer, tells us of discoveries of a man made channel. Detailed observations told to Maitland in the year 1729, by a John Webster who had been a carpenter on the construction of the Great Wet Dock in 1694, indicated at clues that were found when the dock was being built. The particular construction of an old channel led Mailtland to conclude that it was European in orgin. On the basis of Webster's observations Mailtland therefore decreed that the dock was the start of Canute's work. These revelations were made in various publications and one (without the interviews) is related in Chronicles of London Bridge (pub 1825) which is downloadable from the internet

The former entrance lock to Greenland Dock. The possible site of the start of Canute's canal in 1016? Or the location where he made a breach in the river banks?
It is agreed that Canute began his invasion of London by sending ships westwards from what is now Rotherhithe (most likely by a high tide round the south of the Thames and sailing across area that is now the Elephant & Castle.) Canute's fleet entered the Thames further up at either Vauxhall or Bankside. The definitive article on Canute's invasion and his digging of a waterway is from an old publication known as the Anglo-Saxon Chronicle. This tells us the event happened on May 7th 1016 and it tells us of a ditch being dug to allow the ships to by-pass London Bridge. Whilst it doesn't tell us what sort of ditch was made, the most likely explanation in terms of time and effort is a simple trench breached through the Thames southern bank at Rotherhithe in order to flood the land and permit the ships to sail westwards on the high tides

The Great Wet Dock in 1717 (See Notes 1 and 5 below)
British History Online tells us that the canal ('Canute's Trench') ran from the Great Wet Dock through Newington to Chelsea Reach. The same source also tells us that Canute dug a trench not only on the south side, but also on the north and western sides thus surrouding the city completely (see this page.) This information isn't related elsewhere so one wonders what to make of it. If its true then Canute had built something approaching a mini M25 style waterway around the city! Again the question is how could this have been achieved right under the noses of the city's residents and defenders?
Maitalnd's course of the alleged canal
In conclusion Maitland indicated the definitive course of Canute's Canal in one of his books. Whether he was right no-one knows. Maitland claims it took him a considerable amount of time to work out the course. In plotting Maitland's course onto modern day London I find that the alleged canal ran from the Great Wet Dock due westwards across Southwark Park, before bisecting Galleywall Road. It then ran parallel along the Old Kent Road from about where the Tesco superstore is, before crossing that road's alignment somewhere around Bricklayers Arms flyover. It then heads towards Newington Butts, then onto an alignment roughly where the current Upper and Lower Kennington lanes are, before running through the location of Vauxhall station and into the Thames at the lower end of Chelsea Reach

Old view of Greenland Dock, a busy shipping location for 276 years. Commercial shipping ended in 1970. Canute's fleet may have sailed the marshes at this location in 1016