When different canal companies were operating in competition, water was a precious resource and sometimes measures were taken to stop water flowing from one canal to another. Where the Stratford Canal joins the Worcester and Birmingham Canal at King's North was such a measure: a guillotine gate or stop lock .
The lock consists of two guillotine gates suspended from a metal frame over the waterway and lifted or dropped via a chain. This allowed for the two canals to have a different water level (the Stratford was usually a little higher). Now all canals are owned by the same trust water loss is not considered such a problem anymore, the gate has been kept open since 1959.
 Charles Hadfield and John Norris, Waterways to Stratford (David and Charles, 1968) p. 89