Description:Pictured is John Underhill by a development thyristor valve in the High Voltage Test facility at Glover Street in Stafford. This thyristor valve would be one part of an arm of a bridge on a valve, and was made for the Cross Channel Link Project with cable connecting France and the United Kingdom. The cable came ashore between Dover and Folkestone and then went underground to Sellindge Converter Power Station. At the Power Station there were four valve halls. Sellindge Power Station could import and export electricity. At a later date these thyristor valves were replaced by water cooled versions.