Archaeology: Marshland covers its tracks: David Keys reports on London's prehistoric roads

A VAST network of prehistoric roads still exists beneath London's eastern suburbs, according to archaeological research carried out over recent months.

Discoveries made by archaeologists from the Passmore Edwards Museum in Newham, east London, suggest that underneath a 25- square-mile area of former marshland lie the well-preserved remains of around 11,000 miles of Bronze and Iron Age trackways and roads.

Until now, the archaeologists have discovered just five examples, stretching for an estimated combined total of three miles. But so far they have only looked in four places, one particularly successful excavation having yielded two examples. On average, for every 44 cubic metres of excavated peat, the archaeologists are finding one metre of trackway.

'Every time we dig a hole anywhere in the southern parts of the boroughs of Havering, Barking and Newham we come across evidence of prehistoric trackways,' says museum archaeologist Frank Meddens. The discoveries have immense implications for calculating the probable population densities in the London area in prehistoric times.

The tracks and roads discovered so far include the oldest proper road ever found in northern Europe. Made of gravel 2,500 years ago in what is now Dagenham, it was four metres wide and at least a mile long. There is some evidence that it was used to drive cattle and horses along, and probably led to a Thames ferry or some sort of Thames-side Iron Age village built on piles or stilts.

A substantial 3,000-to-3,500- year-old wooden trackway has been found, built across marshland in what is now Beckton. Probably more than a mile long, it had sophisticated construction. Brushwood was laid in a 'cradle' of wooden stakes, arranged in pairs at 45- degree angles every metre. This Bronze Age trackway was 1.3 metres wide and probably led to a marsh village or Thames-side river mooring.

A small 3,300-year-old Middle Bronze Age wooden trackway, probably constructed by fishermen or hunters, was discovered in what is now Rainham. Made of coppiced alder-brushwood, it was half a metre wide and around 300 metres long.

Discovered in Barking were a small 300-metre-long brushwood trackway of probable Bronze Age date, running past a large square timber structure (perhaps a wharf or even a landing stage), and another half-metre wide Bronze Age trackway built of bundles of alder brushwood secured to the ground with wooden pegs. Pottery - indicating a nearby settlement - was found, as were the remains of a cow.

Although estimates based on these discoveries suggest that some 1,100 miles of trackways and roads were built, probably only 20 miles were in use at any one time. Each Thames-side marshland trackway would only have lasted a few decades at most, so there would have been old wooden trackways going out of use and new ones being built continuously for at least 2,000 years and possibly for considerably longer.

The discoveries and the archaeological calculations suggest that in prehistoric times, over a 15-mile length of Thames marshland, there would normally have been one north-south trackway on average half a mile long about every third of a mile.

This implies a much denser population and a much greater degree of economic activity than had previously been thought in the London area.

Now the archaeologists are hoping to find more trackways, and the settlements and riverside installations which they served.

Up to half a dozen excavations are likely to be carried out over the next 12 months - and there is the possibility that the archaeologists may unearth the remains of Iron Age or even Bronze Age boats, landing stages, or even stilt-built marshland villages.

Meanwhile - at a university in Florida - radio-carbon dating tests are being carried out on scraps of wood cut from those trackways discovered so far.

At the University of London, seismologists are about to start studying underground fault lines which snapped one of the trackways in two. These were probably caused by ancient earthquakes.

Other scientists are examining plant and insect remains associated with the trackways, and plan to reconstruct the type of environment prehistoric road-builders had to work in. Examination of the tiny remains of mosquitoes should even reveal whether the people of the marsh are likely to have suffered from malaria.

(Photograph omitted)