Jon Cotton pointed out that although London’s river has been a platform for pageantry amongst other things, it has also menaced the city with flooding, as in 2014 at its western edge; throughout prehistory communities would have been attempting to cope with similar events due to global warming causing sea level rise. London is divided by the river: north and south, but also upstream and downstream, the tidal and non-tidal river, with very different characteristics: upriver exemplified by bucolic scenes reminiscent of “Three Men in a Boat”; downriver, Dickensian, a setting for politics, trade, and tragedy such as the 19th century Princess Alice disaster. Jon outlined ways in which the Thames has impacted on those living along its banks:

1) As a shaper of landscape: Before c450,000BC the Thames rose in North Wales and flowed across Central England to become a tributary of the mighty river Bytham, which was destroyed by the Anglian ice sheet and the Thames was pushed into its present valley. On its new flood plain it has adjusted its course many times in a complicated process, producing a series of terraces as it cut its way deeper, so the higher the terrace, the older, evident in the topography at Trafalgar Square. The terrace occupied by the square dates from c120–160,000 years ago and contains bones of animals such as hippo and lion but no evidence of humans, Britain probably being an island at this time. The higher terrace on which the National Gallery stands was laid down c350 000 years ago and humans were present. The Thames was laying down huge beds of gravel, the digging out of which for construction work has often led to the discovery of ancient artefacts, such as the flint hand axe, now in the British Museum, found along with elephant bones in gravel in the Kings Cross Road; in a quarry at Swanscombe in Kent, three pieces of a female Neanderthal skull were found some years apart. A feature visible on John Rocque’s 1746 map of Syon Park is an old channel of the Thames, which was made use of by Capability Brown in forming the Park’s ornamental lake. Sea level rise is indicated by an entry in Pepys’s diary in which he describes being shown at Blackwall buried yew and hazel trees – one of several drowned forests, probably Bronze Age, along the Thames; near the Southern end of the Millennium Bridge there is evidence of ancient alder carr. Beaver activity, evidence of which has been found at Eton Rowing Lake, at Canning Town and near Runnymede Bridge, also changed the riverine landscape.

By c.3500BC great monuments like the Stanwell Cursus were being laid out; it runs for 4 km and would have required the clearing of woodland, a large number of people to dig plus some kind of Project Manager/Architect. By the Bronze Age there is a recognisable agricultural landscape of fields and farmsteads, and by the Iron Age the development of settlements/villages.

2) As a Provider of Resources: By the 19th century the river was becoming heavily polluted and by the 1950s was essentially dead. Since then there have been concerted, and successful, efforts to restore the river and it now contains many species of fish. That the river once teemed with fish is evidenced by the number of medieval fish weirs which were situated along the river, and work by the Thames Archaeological Survey in the 1990s and more recently the Thames Discovery Programme has discovered on the foreshore the remains of some 30 fish traps, mostly Anglo-Saxon. However, there is little archaeological evidence, such as fish bones, for the consumption of fish in the Neolithic and Iron Age; the eating of fish may have been taboo, perhaps because of the disposal of human remains in the river. However a number of pike jaws found in burials as at Horton and Runnymede Bridge might suggest that the pike was a totemic fish associated with rituals.

3) As an artery of communication: Although by the Neolithic Britain was an island, with the Thames an obvious route in from the sea, few ancient boats have been found there. A distribution map of log boats and sewn boats found in England shows a number in the Humber estuary, but not many in London. The several Late Bronze Age log-boats found at Must Farm in Cambridgeshire would have been used on inland waterways, not for crossing the English Channel. From 2000BC there were sewn plank boats like the one found at Dover – a huge craft perhaps capable of carrying 70 people plus cargo. During the early Neolithic people seem to have entered Britain in succeeding waves from the Continent bringing domestic animals, wheat grain, pottery; a female burial at Blackwall, radio carbon dated to 4200-3900BC, may have been part of the first wave. “Jade” axe heads now appear, tools of perhaps physical and spiritual power, the material for which came from high in the Western Alps.

Yvonne Masson