Hartlepool nuclear power station was forced to shut down a reactor on Saturday because of a fire.

Investigations are continuing into the causes of the fire, which started at around 1.30am on Saturday morning.

French state-owned firm EDF Energy, which runs the plant, said: "A small fire on turbine generator number two was discovered in the early hours of Saturday morning. It was promptly extinguished by a member of staff using a hand-held dry powder extinguisher.

"As is normal practice in such events the fire services attended the site, but were not deployed. Reactor two was safely shut down to enable the event to be properly investigated and dealt with."

The firm said no radioactive material was involved in the incident.

Manchester Councillor Mark Hackett, chairman of the Manchester-based Nuclear Free Local Authorities (NFLA), said: "The NFLA is concerned about this fire incident and we are asking for a full, open inquiry into how it occurred and what were the risks to the plant.

"This is yet another example of the potential risks of nuclear power and of the dangers of building new nuclear power stations.

"We urgently ask the government, the nuclear regulators and the plant concerned why incidents like this keep happening."

In January Europe's largest nuclear facility, Sellafield in Cumbria, declared an alert after discovering higher than usual levels of radioactivity.

Non-essential staff were told to stay away from work.

Bosses said later that the alarm was caused by naturally occurring radon gas.