A series of disastrous investments has left Thurrock Council effectively bankrupt. Services are being cut and council tax raised to try to cover the second biggest deficit ever run up by a local authority. Most of the council's cash was invested in one man's business. Liam Kavanagh promised his solar farms would provide a safe return, but his companies have been wound up and the council faces big losses. Bronagh Munro reveals how the millionaire businessman spent council cash on himself and left local people to pay the price