This lock which is seen here looking downwards, gives access between Limehouse Basin and the River Thames. It is a modern lock which has replaced* the huge ship lock which still existed up to at least 1977 and which could take ships up to 300ft long x 60ft beam, the purpose being to allow such vessels to moor off the tideway. There was also at one time a barge lock 79ft x 14ft 6ins, but this was filled in earlier.
*probably around 1980.
By Nelson's Dockyard on the south bank of the Thames in Limehouse Reach is a headland known as 'Cuckold's Point' TQ365803. According to BREWER (1999 edition) it got that name because "King John successfully courted a labourer's wife there". Surely worth a piccy then!