Scuffles broke out between anti-fracking protesters and police after energy company Cuadrilla finally started exploratory drilling.
Two people, a 19-year-old woman and a man, were arrested on suspicion of assaulting police as tensions remained high near Balcombe, West Sussex.
Activists from across the UK have descended on the outskirts of the village which has become a national focal point for the campaign against hydraulic fracturing, or fracking.
Protests have delayed Cuadrilla’s plans to drill a 3,000ft vertical well in a project lasting up to three months, but work finally got underway yesterday.
Although the energy firm has said it has no plans to use fracking, villagers fear it will at some point in the future.
Vanessa Vine, of Frack Free Sussex, said: “I’m absolutely livid and incredulous. This is a violation of our geology that could threaten our water, fresh air and our children. There is a political mania around this. I have no faith in our governmental process, and I feel like Balcombe is sacrificial.”
Fracking involves high pressure liquid being pumped deep underground to split shale rock and release gas supplies.
Opponents highlight concerns about potential water contamination and environmental damage, as well as small-scale earthquakes.
Cuadrilla’s chief executive, Francis Egan, has tried to soothe concerns by saying his firm has “no intention of ruining the countryside”. Although fracking is not part of its plans near Balcombe, Mr Egan insisted it was safe.
As the drilling started, protesters vowed not to let up. Ms Vine said: “This is going to spark the biggest environmental movement we have seen.”