The River Thames begins in a meadow near Cirencester, but where exactly does it end? It's a crucially important question if you're the organisation responsible for the Thames and all that sail on her.
The Crown used to hold the fishing rights for the lower reaches of the River Thames, but King Richard I needed money during the Crusades so sold them on to the City of London. In 1857 those rights passed to the Thames Conservancy and in 1909 to the Port of London Authority who are still responsible for navigation on the lower Thames. As early as the 13th century stone markers were placed at the mouth of the estuary to mark the point where the City's jurisdiction ended, and the Essex version was positioned in the mud just off Southend.
This is the Crow Stone, an obelisk officially washed on one side by a river and on the other side by the sea. Specifically it's in Chalkwell, off the esplanade between Westcliff and Leigh-on-Sea, a few dozen metres below the high tide line. An inscription on the obelisk names the Lord Mayor of London and two sheriffs at time of installation. If you're thinking that the obelisk doesn't look particularly medieval you'd be right, this is an 1837 replacement, whose predecessor was itself a replacement dating back to 1755. The original Crow Stone is long gone.
Apology: When I got to Chalkwell on Monday afternoon the tide was in so the Crow Stone lay inaccessible in the water. It wasn't yet proper high tide, still two hours short, but the Thames had already crept up the mudflats to almost the top of the beach. I was therefore unable to walk down and inspect the obelisk close up, nor read the inscription, so had to make do with taking blurry photos from the promenade. If I'd started my day here rather than walking Southend Pier first then the tide would have been low enough to permit access, but I failed to plan ahead because I did not make the Crow Stone the focus of my visit.
Apology: I've walked this way before, of course, but failed to make the most of the opportunity. This was in 2015 when, as part of an interactive blogging feature, my readership sent me to Westcliff and I just happened to be passing Chalkwell at a time when the tide was a long way out. But did I go down onto the beach and investigate the Crow Stone? No I did not. Perhaps I was concerned about getting my trainers muddy, although to be fair the beach down as far as the obelisk looked pretty solid. I guess I wasn't interested enough in its monumental story at the time. Sorry.
Apology: The 1755 version of the Crow Stone wasn't lost but relocated for safe keeping, and can currently be seen in Priory Park in Prittlewell. Specifically it's inside the grounds of Prittlewell Priory, probably the most heritageworthy site hereabouts, which was adopted by the borough council in 1922 as a local museum. I've long intended to write a post about Southend's collection of museums and galleries but have never got round to it, which is a shame because I'd then have relevant additional reportage to bring depth to this feature. Also the Priory's closed on Mondays so I couldn't have gone this time anyway.
But that's just one side of the estuary. A dividing line needs two ends and the Kent marker is located on the Isle of Grain, five miles distant. It's called the London Stone and can be found not far from Allhallows-on-Sea at the mouth of Yantlet Creek, hence the line across the estuary is often called the Yantlet Line. The monument stands about eight metres tall, atop a concrete plinth which helps raise it above tidal waters, this time with a mostly illegible inscription. It's also on the wrong side of the creek to be easily accessible, being on the edge of an MoD Danger Area with no public footpaths.
Apology: I have been to Allhallows-on-Sea as part of a fragmented island safari in 2014. I did get within a mile of the Yantlet Stone on the edge of the holiday park, but there was alas no time for a trip along the seawall to the creekside before the next bus departed. I did however grab this grainy photo of the mouth of Yantlet Creek over the roof of a chalet. The taller structure which looks like a mini Eiffel Tower is a navigational marker and the Yantlet Stone is the faint cluster of pixels on a separate finger to the left. Sorry, I have rarely blogged a photo as poor as this.
Another London Stone exists at the upper limit of the City of London's original jurisdiction. It's in Staines, which was once the highest point on the tidal Thames where a change in river level was discernible twice a day. The first stone was installed circa 1280 beside Staines Bridge, and in the mid 18th century a newer two-foot plinth was moved upstream to the Lammas Pleasure Ground. The London Stone currently in situ by the river is a replica, with the original having been shipped off somewhere safer... which since 2004 has been Spelthorne Museum inside Staines Library. In good news I have actually been there and seen it inside its glass case, and here it is.
Apology: What I didn't manage to do in 2015 is find the outdoor replica. I went to the Lammas Pleasure Ground, because that's where the arrow on the map in the museum pointed, but spent a fruitless fifteen minutes finding nothing. My retrospective belief is that the replica can be found closer to Staines Bridge, but that was the one stretch of riverside I didn't walk along having been seduced by the main shopping street instead. Apologies, it's not much cop telling you where something historic might be located based on inadequate local research.
Today the Yantlet Line is still used by the Port of London Authority when deciding whether river duties are chargeable on passenger vessels. But for broader reasons of navigation and oversight its Thames boundary now pokes out much further into the North Sea, embracing Shoeburyness, a lighthouse off Frinton and most of the coast of the Isle of Sheppey. The Crow Stone has been almost completely superseded.
"the seaward limit" means lines drawn from latitude 51° 37' 00” north, longitude 00° 57' 19" east (Foulness Point in the county of Essex) to latitude 51° 46' 05" north, longitude 01° 20' 32" east (Gunfleet Old Lighthouse) and thence to latitude 51° 26' 36" north, longitude 01° 25' 30" east and thence to latitude 51° 24' 55" north, longitude 00° 54' 21" east (Warden Point in the county of Kent).
Apology: Sorry, I haven't properly visited any of these Thames markers and didn't manage a single decent up-close photo. You'll be wanting to read the considerably more comprehensive account blogged by A London Inheritance last summer which includes a full report on the Crow Stone and a perilous hike across the Yantlet Creek. I merely walked past at a distance. The Thames flows out to sea regardless.