Twelve people were killed and at least 25 others injured after a gunman carried out a series of shootings in Cumbria, northern England, local police confirmed on Wednesday.

Police in Cumbria, about 560 km northwest of London, said the body of the suspected attacker, a 52-year-old taxi driver Derrick Bird, was found 20 miles away in woods near the hamlet of Boot later.

Police said they had recovered two weapons, adding Bird was believed to have taken his own life.

British Prime Minister David Cameron said earlier in the House of Commons that he was "alarmed and shocked" by the shootings.

"I regret to report that a number of people have been shot and at least five people have died," he said. "the government will do everything it possibly can to help the local community and those affected."

The BBC reported that there have been 11 separate shooting incidents since the first killing was reported in the coastal town of Whitehaven.

"When lives and communities are suddenly shattered in this way, our thoughts should be with all those caught up in these tragic events, especially the families and friends of those killed or injured," he said.

"I can confirm that we've found a body in a wooded area near Boot which we believe to be Bird, together with a firearm," said Stuart Hyde, deputy chief constable of the Cumbria Police.

"Our focus is now on the movements of Bird this morning. We believe there are a number of fatalities and injuries," said a Cumbria police spokeswoman.

A Home Office spokeswoman said the Home Secretary was monitoring the situation in Cumbria with an increasing sense of alarm.