Yantlet Creek is the creek draining into the River Thames that separated the Isle of Grain from the Hoo peninsula. It once connected the River Medway with the River Thames and made the Isle of Grain a true island. The creek silted up and now drains the area of The Isle of Grain and Allhallows Marshes. A monument known as the London Stone is located at its mouth and marks the limit of the City of London's ownership of the Thames. Yantlet gives its name to the Yantlet Reach on the Thames, and in its time has been used as point where the river became the estuary. The Yantlet Creek area is designated a special landscape area in the Medway Local Plan. It is also part of the South Thames Estuary and Marshes special protection area (SPA), and within the Natural Area of the Greater Thames Estuary and Site of Special Scientific Interest (SSSI). History In mediaeval times the Yantlet Creek (on the Thames) and Colemouth Creek (on the Medway) once formed a single watercourse, separating the Isle of Grain from the rest of the Hoo peninsula and providing a shipping channel from the Thames to the Medway under the conservancy of the City of London. It was the preferred way for Medway boatmen to reach the London River, being shorter and less hazardous than passing by Queenborough. A substantial single arch stone bridge, known as Grain Bridge, crossed the creek at a point on the line of the present day A228. It allowed both the passage of boats along the creek, and the passage of road traffic over to Isle of Grain village. The tides from the Thames and the Medway came together at the bridge. The bridge which may have been of Saxon or Norman origin some time prior to 1760. It was replaced by a causeway which at first may have been more like a ford at low tide, forming a spitway at high tide. Over decade the channel silted up. Whether the blockage caused by collapse of the bridge caused the silting, or neglect as the channel needed to be dredged has not been established. Over sixty years the causeway was raised, built over the creek and the locals saw Colemouth and Yantlets as separate waterways. The City of London remembered this as a single waterway over which it had rights of navigation. The City of