The Sellafield nuclear reprocessing plant in Cumbria is an easy target for a terrorist attack, it is claimed.

The Environment Minister Michael Meacher accused Conservative spokesman Jonathan Sayeed of "irresponsible" behaviour after he claimed a passenger jet attack on the plant will render a 400-mile area around Sellafield uninhabitable.

Speaking in the House of Commons, Mr Meacher condemned the frontbench MP for drawing attention to the "exposure of a major nuclear plant" in public.

Mr Sayeed claims a passenger jet would take just 30 seconds to traverse the air exclusion zone around Sellafield.

He said: "There is an urgent need for the imposition of new security measures, perhaps involving precautions as basic as barrage balloons, to deal with this threat until safer storage of fissile material is achieved."

But Mr Meacher said: "I find it absolutely extraordinary that a frontbench spokesman should draw attention to the exposure of a major nuclear plant in this way."

Mr Meacher said the government is aware of security issues in the wake of the 11 September terror attacks.