Severn Trent Water
The complex accounting trick started in March 2017 when a shell company, with no money or assets, called Severn Trent Trimpley was set up as part of the group. Another Severn Trent company called Severn Trent Draycote - which owns the water company - agreed to buy Trimpley for £2.
Trimpley then issued additional shares and Draycote bought them for a staggering £3bn.
No money actually changed hands, however, as Draycote paid Trimpley with a £3bn loan note - effectively an IOU. But, on paper, Trimpley immediately appeared to be worth £3bn because it had the IOU.
Severn Trent Water then acquired 49% of Trimpley - and that investment was valued in the water company's accounts at £1.47bn. A hugely valuable asset appears to have been created for Severn Trent Water out of thin air.
Panorama discovered the Trimpley investment through the work of retired auditor Stanley Root.