English: Remains of channel to old side .lock At this point a channel used to lead northwards from the main line of the canal to a side lock (known as Fleet Lock) which gave boats access to Fleet Mill, on the south side of the river above the weir. But Fleet Mill closed in the inter-war period, after which this facility was no longer needed and the channel became overgrown and unnavigable. The side lock itself seems to have completely gone, but it is difficult to access the site.