Drilling for oil close to the West Sussex village of Balcombe has begun following a week of blockades and protests by anti-fracking activists who fear that the possible use of the extraction method could lead to the pollution of water courses...Protesters who have been occupying the entrance to the drill...were distraught at the news...[Cuadrilla] has not ruled out the possibility of using...fracking...Opponents are afraid that fracking liquids could poison waterways in the area and could even lead to earth tremors, which they say could jeopardise the safety of a nearby railway line running into London...Cuadrilla...[says it has]"no intention of ruining the countryside and won't ruin the countryside". He said hydraulic fracturing was safe and would not pose a threat to the public or people's drinking water. [refers to BP]