An amateur archaeologist has discovered a Roman amphitheatre in Norfolk with the help of home-made remote-sensing equipment.
Peter Cott, a retired electrical engineer, found the 1, 900-year-old stone arena by measuring differences in electrical resistance in the ground.
The amphitheatre, near Norwich, was oval and measured up to 80 metres from north to south and up to 70 metres from east to west. It would have accommodated between 5,000 and 10,000 spectators.
The main entrance faced south, while at the northern end there was a short corridor leading to a series of rooms, almost certainly once used to accommodate gladiators and animals waiting to do battle.
The arena itself was about 40 metres long and 34 metres wide and Mr Cott's remote sensing equipment even succeeded in recording part of what was probably its metalled surface.
At each side of the arena there appears to have been a small alcove, probably to house statues of the Roman goddess of retribution, Nemesis.
Mr Cott's survey yielded data, which when processed in a computer, produces the equivalent of an X-ray of what lies beneath the ground. Built in the late 1st or 2nd century AD, the amphitheatre would have been used for gladiatorial contests, fights between animals and men, often convicted criminals, and animal-baiting.
It was constructed just south of the Roman town of Venta Icenorum, of which only the defences still survive. Venta, near the modern village of Caistor St Edmund, was in Roman times the imperially designated purpose- built new capital of the Iceni tribe after its revolt under Boudicca had been crushed by the Roman military.
The site of the ancient town is today owned and managed by the Norfolk Archaeological Trust, in co-operation with whom Mr Cott has been carrying out his work.
Ever since aerial reconnaissance work in 1977, archaeologists had speculated that a dark oval patch visible from the air in a field south of Venta might be the remnants of an amphitheatre. Now Mr Cott's work has proved that the archaeological speculation was well-founded.
The newly discovered Norfolk amphitheatre is one of only 10 known to exist in Britain and was almost certainly built within 100 years of the construction of the Roman empire's greatest amphitheatre, the Colosseum in Rome.