Though operations are in their infancy, protests against hydraulic fracturing in the United Kingdom have turned violent, corporate officials said.

A manager working for Dart Energy was assaulted by a protester last month near the company's drilling site in Daneshill. The company's chief executive officer, John McGoldrick, said the attacks were "cowardly."

One member of Dart's staff told the Daily Telegraph on condition of anonymity Sunday the protests have "turned very nasty."

The company hasn't used the controversial drilling practice known also as fracking. It's been conducting an exploration campaign to examine the reserve potential.

Though British energy companies have looked to replicate the successes from North American shale, fracking is a new phenomenon in the country.

The government says shale could ensure energy security for a country where net natural gas imports are on pace to increase from 45 percent of demand in 2011 to 76 percent by 2030.