Excavating for a new underground railway has revealed a lot about London’s history, John Westbrooke reports

Digging tunnels for Crossrail has already disrupted central London for years, and the fast-track Elizabeth Line won’t be fully functional for a few more. But a useful by-product can be enjoyed right now: objects unearthed by archaeologists are on show at the Museum of London Docklands.

The line will be 118km long, with 42 km (26 miles) of tunnels going under the centre of a city that was founded in Roman times – but an area that has been in use much, much longer.

From Woolwich, near one of the eastern ends of the tunnel, comes a scattering of flint flakes, created when a late Mesolithic tool worker was making a flint axe, sometime around 6000BC.

At Royal Oak, near the western end, bison bones were found, going back as far as 66,000BC. In those days the Thames valley was miles wide, and the river flowed into the Rhine, because Britain was still attached to the continent and animals could just walk across without getting their feet wet.

Going even further back, a woolly mammoth’s jawbone, from maybe 100,000 years ago, has been found at Canary Wharf, along with some amber, thought to be 55 million years old and very rare in this part of the world. Both are still being studied, and so not in the exhibition, but they’re casting new light on London’s past.

Under central London, the tunnels go deep to avoid existing tube lines and other subterranean services. The finds are mostly from more recent eras; and some remain a puzzle. More than 50 human skulls were found in the valley of the Walbrook (long since covered up); they date from Roman times but nobody knows what they were doing there. It has been suggested that the river eroded part of a cemetery, but that doesn’t explain why there were so many heads and so few other bones.

Among things you might not have heard of are hipposandals. Hippo in this case is Greek for horse, and these are temporary iron shoes for horses or oxen, made to provide a grip on smooth streets. They were found near the Roman road outside the city walls, and perhaps indicate an area where horses were grazed, stabled or hired.

Into the Middle Ages and beyond, finds have included pilgrims’ badges, money from Venice, bone ice skates (winters were a lot nippier during the Little Ice Age of 1300 to 1850), leather shoes preserved in damp ground, a Tudor bowling ball – and more bones.

A shaft in Charterhouse Square uncovered 25 skeletons in a cemetery founded in 1348 during the Black Death, which killed about half the population of London. DNA tests of teeth showed several had the plague pathogen, Yersinia pestis. When the disease returned in 1665, the burial ground at St Mary Bethlehem, the original “Bedlam”, was used as a plague pit. At least five of the skeletons there had Y. pestis too. Fortunately, that was the last of the outbreaks.

But modern methods of analysis have revealed much more than this. Some skeletons had nodes on the vertebrae indicating that they carried heavy loads a lot. Many could be traced to different parts of Britain – but those who were found to have suffered most stress in childhood were all native Londoners. The city has always attracted incomers, but not for its relaxed and healthy lifestyle.

Victorian finds include art deco railway tea cups from the GWR depot at Old Oak Common, and a saucy chamberpot from a former manor house in Stepney.

Though it’s hard now to imagine big industries in the middle of a city, the digging has shown how recently this was the case. (The last of central London’s industries, the newspapers of Fleet Street, left barely 20 years ago.)

Crosse & Blackwell’s pickle factory was on Charing Cross Road, near where Foyles bookshop is now. They moved out in 1921, leaving behind a brick cistern containing 13,000 jars and bottles from various companies, many in excellent condition. The smell for which the factory was once notorious has gone but the exhibition organisers have kindly provided some typical odours in jars for visitors to sniff.

Even heavier industry was uncovered out east on the site of the Thames Iron Works, where early iron ships were built for the navy, the queen and the pope. A big chain on display may have been used to slow ships down as they were launched – one, the Albion battleship, drew 30,000 to see its launch in 1898, but the backwash it caused as it hit the water swamped a bridge, and 38 viewers died. Historic newsreel footage records the event.

By way of a coda, there are photos of buildings demolished in the course of excavations, including the London Astoria cinema/ballroom/theatre/music venue, built on the Crosse & Blackwell site. They’re too recent to yield up much archaeology, but at least records have been kept of their existence, something for the goths and punks who used to gather there to look back on with nostalgia in their old age.

Similar exhibitions were held, briefly, several years ago, when fewer objects had been found. This one runs at the Museum of London Docklands on West Quay until 3 September 2017. Entry to the museum and the exhibition is free.

www.museumoflondon.org.uk/museum-london-docklands/whats-on/exhibitions/tunnel-archaeology-crossrail