Security at Sellafield nuclear plant in Cumbria has been tightened it has been announced on the eve of the anniversary of the 11 September attacks on America.

Environmental groups have claimed that in the past year the plant has been vulnerable to a terrorist strike.

Safeguards at the nuclear reprocessing plant have been improved, including moving speed traps away from key buildings, with other measures to remain secret for security reasons.

Plant owners British Nuclear Fuels Limited (BNFL) say they have no reason to believe the complex will come under attack, but that last year's events have prompted a close inspection of security.

Visitors vetted

The firm's head of services, Paul Croft, said: "I think the events of 11 September, 2001, was a milestone for everybody, not just in the UK, or just in the nuclear industry, but worldwide.

"Our assumptions had to be revisited, so whilst I believe the site was secure prior to 11 September, we needed to revisit and review our arrangements.

"We have made some changes in light of that, from the recommendations that we have had from our regulator."

All visitors are escorted onto the site, with many being vetted before they enter Sellafield.

Safety procedures

Anti-nuclear campaigners claim a passenger jet would take just 30 seconds to cross the air exclusion zone around Sellafield.

There is an aircraft no-fly zone over Sellafield, which goes to 2,200 feet above the site, and in a 1.5 mile circumference around the site.

But Mr Croft said: "I believe we are safe because I know the people we have on the site, the procedures, and the exercises we have carried out.

"We are as safe as we ever will be."