The sun is climbing steadily into a pollution-tinged sky as I wrestle with my vertigo on a wall high above the Thames in London. I am catching the early tide for a spot of mudlarking and the thin metal ladder I am about to descend is the only access to this part of the river’s foreshore. So, at 5.13am, with a tumbling tummy, I swing my legs over the edge and begin my white-knuckle climb down to the foreshore.

Following in the footsteps of the original Victorian mudlarks, who picked the foreshore for a living, I am one of a relatively small number of people who search for the historic flotsam and jetsam that emerges every day from the mud of the Thames.

For thousands of years human beings have been losing their possessions and dumping their rubbish in the Thames, making it the longest and most varied archeological site in the world. Twice a day the water recedes with the tide to reveal the foreshore. For those in the know, these muddy stretches provide a tangible link with the past and an oasis of calm in a chaotic city.

I am not an archeologist or even a treasure hunter, obsessively searching for gold and coins with a metal detector (although I have found both without one). I am a seeker and collector of pieces of human history. My finds sometimes amount to no more than a button, a broken clay pipe or a shard of pottery, but each one is a precious window into past lives lived on and around the capital’s famous river.

I am lucky enough to pursue this unusual pastime as a hobby, but in the 19th century mudlarks were forced to the foreshore through need and desperation. At the time, London was the gateway to an empire and the Thames jostled with ships from every corner of the globe.

From clay pipes to 500-year-old shoes: some of Lara’s finds. Photograph: Lara Maiklem

Among this chaos, opportunities opened up for those willing or desperate enough to pursue them. Mudlarks were one such sorry band: children and old people who survived by wading through the foul-smelling mud to collect anything they could sell, such as rags, coal and rope.

Mine is a happier tale. I began walking the Thames foreshore almost 20 years ago as a way of finding peace, solitude and sanity in one of the largest cities on earth. It has seen me through the death of my father and the confusion of early parenthood. Its strong, steady flow has calmed my racing mind and the ordinary, and often very personal, things I have found along its banks have taught me something of the fleeting moments that make up a life.

Much of the foreshore in central London is covered with building rubble: over 2,000 years of destruction and rebuilding, from Boudicca to the blitz. Ancient fragments of Roman heating systems lie among the Tudor bricks and medieval floor tiles – sometimes a tile turns up showing the paw print of a long-forgotten dog or cat.

Domestic waste – animal bones and oyster shells – lie in drifts, testament to London’s appetite over the centuries. Shards of pottery from the vessels in which meals were served and cooked date back to Roman times, and beyond, and among it all are scattered what look like small white sticks. These are the broken stems of clay pipes, disposed of in much the same way as cigarette ends are today. The clue to their age lies in the pipe bowls themselves, which are plentiful in certain parts of the foreshore. Tobacco was brought to England from America in the 1580s and the earliest pipe bowls are tiny because tobacco was rare and expensive.

Lara searches the foreshore for remnants of the past. Photograph: Christian Sinibaldi/The Guardian

In certain parts of the foreshore the mud literally prickles with thousands of handmade pins. They can be found in such large numbers simply because so many were used, and subsequently lost. They date from medieval times to the industrial revolution, when the process was mechanised. Men would give their wives money to buy their pins, which were used for holding together everything from ruffs and dresses, to baby swaddling and shrouds.

Over the years I’ve eased buttons, lace ends, buckles, dress hooks and thimbles from the mud and plucked clay wig curlers, wooden nit combs, needles, beads and bodkins from its surface. I’ve even found a beautifully decorated gold lace end, with possible links to the Tudor court, lying on the mud just waiting to be picked up.

But perhaps the most personal objects are leather shoes. The anaerobic properties of Thames mud means that its treasures are cocooned in an oxygen-free environment, which preserves them as if they had been lost just yesterday. My Tudor shoe is a moment trapped in time, with wear creases across the top and indentations in the sole from the toes and heel of the last person to wear it more than 500 years ago.

Love tokens are also intensely personal finds. It became fashionable in the 17th century for young men to bend a silver sixpence for their beloved in lieu of a ring. If she liked him she would keep it, but a good number also ended up in the river. Even modern wedding rings are a fairly regular foreshore finds, which suggests that the Thames is still a willing recipient of broken hearts, dreams, and even the ultimate act of a broken spirit – suicide. I’ll never forget the young man I saw washed up on the foreshore some months ago.

As London wakes up around me and the commuters begin their ant-like march over London Bridge I’m reminded of the unique tranquility of this urban space, which is there for all to enjoy. But with this gift comes responsibility. Thankfully there are rules and regulations to protect the foreshore and the heritage it contains.

In my opinion there is no need to dig holes in the foreshore, or even use a metal detector; a keen eye and some patience will reveal enough to satisfy most curiosities. Most of what I know about history I have learnt from the foreshore, but more precious than all the beautiful artefacts I have found is the peace and solitude it has given me.

Lara Maiklem runs London Mudlark, the largest online mudlarking community. Follow Guardian Cities on Twitter and Facebook to join the discussion