Operations like reprocessing at Sellafield simply could not withstand such an attack without devastating consequences

Caroline Lucas Green MEP

Both Irish Prime Minister Bertie Ahern and Sinn Fein have already called for Sellafield in Cumbria to be shut because of terror fears and environmental worries.

French defence officials have already tightened security around Europe's largest nuclear processing plant, at La Hague in North West France.

Security not disclosed

A Department for Trade and Industry (DTI) spokesman said the government did not disclose what security measures were in place at nuclear sites.

Stringent security measures were used at all nuclear sites and were constantly under review, he said.

Lucas has given a stark risk warning

Those were being reviewed again in the wake of the 11 September atrocities by industry regulators the Office for Civil Nuclear Security and the Health and Safety Executive.

The Greens say the UK must follow the French in putting anti-aircraft defences around nuclear plants and start urgent talks on closing all nuclear facilities as soon as possible.

Green MEP Caroline Lucas said: "After 11 September, all nuclear facilities must be shut down as rapidly as possible.

New threats

"Operations like reprocessing at Sellafield were never constructed with a terrorist attack in mind, and simply could not withstand such an attack without devastating consequences."

Dr Lucas said 44 times as much radioactivity as the Chernobyl disaster would be released if a plane crashed into one of the key structures at Sellafield.

Her party also wants the government to withhold the operating licence of the new mixed oxide (Mox) fuel facility at Sellafield until there is analysis is published on how it could withstand an attack.

While the Greens went further than others in their call for action, MEPs of all political colours argued in the European Parliament for stricter safety measures at nuclear plants.

'Reassessment needed'

Conservative MEP Giles Chichester, a party industry spokesman, said: "The events of 11 September call for a reassessment of the risks of attacks on installations that we previously regarded as secure."

The Home Office says protecting the UK's key facilities and utilities in the wake of the attacks has been discussed by the government's Civil Contengencies Committee.

Earlier this month Home Secretary David Blunkett said: "We are doing everything we can be doing not only to protect potential high profile targets but also essential services."

Bertie Ahern has accused Tony Blair of timing the announcement that the Mox operation would open, made at the start of October, to coincide with the aftermath of the US attacks.

The risk from the site was "unacceptably increased" by the decision, he claimed, branding Sellafield the biggest threat to Ireland's environment.