Shale gas is natural gas trapped under sedimentary rock, which is extracted using a method known as hydraulic fracturing, or "fracking". There are large reserves of shale gas in Lancashire. Some people think that using shale gas could be a solution to Britain's energy needs. Other people think that fracking is a dangerous technique that risks contaminating ground water and causing minor earthquakes. From what you have seen or heard about the issue, do you think Britain should or should not start extracting shale gas?