Transcribing an interview recording is usually a chore, but this one I enjoyed. Not only because the subject of the interview – the writer and journalist Caroline Crampton – says some fascinating things about the Thames estuary, the subject of her excellent book, but also because of the other stuff going on: the honking from a V-squadron of low-flying geese; the morose, shrill piping of an oystercatcher; the summery burbling of a skylark.

We haven’t even reached the venue she has chosen for our interview, Cliffe Fort, on the Hoo peninsula in north Kent, but we are walking and talking and my recorder is on. There is the crunchy mechanical rumble of a conveyor belt bringing gravel inland to the aggregate plant. It cuts us off; we went the wrong way. “Classic Thames mistake, to think we could just head straight for the thing,” says Crampton, 31, consulting her Ordnance Survey map.

Eventually, we reach the estuary and sit down on the embankment of the Saxon Shore Way, the path that follows the coastline as it was in Roman times, before the North Kent Marshes came into existence. Behind us is Cliffe Fort – boarded up, graffitied, surrounded by a green sea of nettles – which was built in the 1860s to protect the entrance of the Thames from potential attack by the French. In front is the river itself, murky and brown even on a gorgeous spring day, taking one final turn before heading out to the North Sea. “It’s presenting a very nice face to you today,” says Crampton, not without pride.

A dredger chugs inelegantly downstream, probably to the container port of London Gateway, the waters of which need to be kept deep to allow in huge ships at all states of the tide, she says. Across the peninsula, we can see its cranes, a platoon of enormous mechanical storks marching across the marshes.

Facebook Twitter Pinterest The enormous mechanical storks of London Gateway. Photograph: Jill Mead/The Guardian

This may not immediately strike visitors as a place of inspiration, stories, ideas or beauty – but it is, say Crampton. She even finds beauty in the mud at low tide. “I love it when it looks all pillowy and dimpled when the streams cut a really deep course through it, making those little cushions,” she says. “Although it is very treacherous.”

What is so special about this muddy brown estuary? “Because of London being such a huge and historic place on its own, and then lots of people coming through here for different reasons, from all over the world, I think a lot of mythology is imbibed in this area,” she says. “I suppose to me it seems important because I grew up here and I’ve thought about it a lot.”

If we could turn the tide of time and sit here on other days, between when the Romans were in town and today, we would see other vessels passing. The longship of Thorkell the Tall in 1009, perhaps, on his way to take over south-east England; HMS Temeraire from JMW Turner’s famous painting, no longer fighting in Nelson’s fleet, but being tugged ignominiously to the maritime knacker’s yard at Rotherhithe under a funereal sky in 1838; a clipper called Torrens, with the seaman “J Conrad Korzemowin” on board, on his last voyage in 1893 before giving up seafaring and taking up writing; the Empire Windrush, docking in Tilbury in 1948, bringing with it a new generation of Britons. Or, in 1984, a 33ft sailing yacht called Scherzo, with a young couple on board who had sailed 8,000 miles from Cape Town.

It’s a very hazardous place. There are more wrecks per square mile than anywhere else in the UK Caroline Crampton

The couple were Crampton’s parents. They had left the political horror and economic uncertainty of South Africa for an adventure and to begin a new life. And they came up the Thames. Although Crampton didn’t know it yet (because she hadn’t been born), the river was a part of her.

After spending months living on Scherzo in St Katharine Docks by Tower Bridge, her parents settled on the Medway. Crampton – like the Temeraire – was born in Chatham, Kent, over Higham hill behind us. Her childhood weekends and holidays were spent sailing and exploring muddy creeks, but not without resentment: her teenage friends were going to Disneyland and Spain. At some point, though, the estuary became the place she loved best in the world – a place that she would be drawn to again and again.

Unlike Peter Ackroyd’s Thames book, which devotes only six of its 500 pages to what happens east of Greenwich, the estuary is where Crampton’s book, The Way to the Sea, gets going. A literary dredger, she chugs downstream slowly (but with much more elegance than the literal dredger), scooping up stories of maritime disasters, floods and cholera, slavery, prison hulks, political upheaval, the rise of the far right, sewerage. When she is not on the estuary, she is travelling by foot along the Thames Path, which we are sitting beside. She finds joy – mudlarkers and archeologists, happy sailing trips, the vast skies and light that Turner sought to capture – as well as sorrow and mud. Beautiful mud, remember. She twists her own story, and the stories of the other storytellers, into the tale of the river, splicing it into something not only scholarly, but purposeful and personal, too.

Facebook Twitter Pinterest Crampton and Sam Wollaston indulge in a spot of mudlarking. Photograph: Jill Mead/The Guardian

Joseph Conrad – yes, he was the sailor with the Polish name on the Torrens – is a hero of Crampton’s and a big influence on her. He also found the estuary exciting, she says. “I think for the same reason I do: because it is in some ways quite blank. You can fill it yourself with your own ideas of what you want it to be.” He called it the “mysterious vastness” and settled on the other side, at Stanford-le-Hope in Essex.

Dickens was another local; he had a place in Higham, on the peninsula behind us. Cooling church, thought to be the setting for Pip’s encounter with Magwitch at the beginning of Great Expectations, is a little beyond. Crampton remembers reading it, partly at home, partly on weekend sailing trips. “I saw the TV adaptation first, which is not the way round you’re supposed to do it, I’m sure. It was filmed in the Medway at a place called Stangate Creek, where we used to go all the time. I thought it was amazing they’d put this muddy place I thought was great but no one else did on television, and my father went: ‘You know, it’s a book as well.’ It was so exciting to read about the places I knew, but 100 years before, in the fictional bleakness of Dickens’s imagination.”

There were 10 prison hulks along the river, holding 4,446 people in 1826. “A wicked Noah’s Ark,” Dickens called Magwitch’s, “cribbed and barred and moored by massive rusty chains.” There is nothing left of them today, but if you close your eyes it is easy to hear the clanking of leg irons or a shot ringing out across the salt marshes, a warning to the locals that an escape has been made and a criminal is on the loose.

There is the ghost of a vessel here on the foreshore, a Danish schooner called the Hans Egede. It was built in 1922, damaged by fire off Dover in 1955 and dumped here. The tide is now at its lowest and the wreck lies like a beached whale, ribs picked by time and tide. We step out over Crampton’s muddy cushions – gingerly; she is right, it is treacherous – to play Jonah and explore the vessel’s slimy planks.

Crampton describes the estuary as “wreck central. Partly because of the volume of shipping that comes into the Thames; also the sands, tides, tidal range and bad weather. It’s a very hazardous place. There are more wrecks per square mile than anywhere else in the UK. I do like wrecks – they’re amazing and fascinating – but just a bit scary.”

Facebook Twitter Pinterest Part of Cliffe Fort, built originally in the 1860s to withstand a potential French attack. Photograph: Jill Mead/The Guardian

Probably the best known – and most feared – is the SS Richard Montgomery, a US Liberty ship that dragged its anchor and was wrecked on a sandbank off Sheerness, round the corner, in 1944. On board – still on board – is 1,400 tonnes of explosives. Locally, they call it the Doomsday Ship.

Time for a little light mudlarking before the tide comes back in. Scavaging the shore like the oystercatchers, looking for something of value, has become an unlikely “thing” on Instagram. It is probably better upriver in the capital, where the lives of Londoners past can be picked over, Crampton says. “It’s quite boring most of the time, but then every time you’re just about to go home you’ll see something and stay for another two hours.”

The sound of boot in Thames mud is a lovely, squelchy one. Rude, even. (Listening back is getting even more fun.) Our haul, after considerably less than two hours, includes the tube part of a Victorian clay pipe, plus a few bits of broken ceramics, some “sea glass” (bits of broken bottle worn smooth), a lump of coal, a fan belt, a trainer, a Hindu pamphlet and a chocolate wrapper. I don’t think the British Museum, or even Instagram, is going to get very excited about it.

But if the estuary hasn’t given up much of material value, it has made up for it in other ways. Because, as Crampton writes in her epilogue: “More than just the physical flotsam transported by the river, this water is the repository for every silent sorrow and hidden joy ever whispered down by the Thames at twilight and carried away by the stream.” In that, it doesn’t disappoint.

The Way to the Sea by Caroline Crampton is published by Granta

• This article was amended on 4 June 2019. The author’s mudlarking produced a Hindu, rather than Buddhist, pamphlet.