British security sources raise doubts over US claims about 'dirty bomber'

British and European security officials are highly sceptical of American claims that the alleged "dirty bomb" plotter, Abdullah al-Muhajir, was preparing to unleash a radioactive attack.

British sources point out that despite extensive inquiries, no evidence has been produced to show that he had access to the radioactive material needed to build the bomb, or indeed that he had even worked out a time or place to launch the attack.

The most that could be said about Mr Muhajir, a former member of a Chicago street gang now allegedly working for al-Qa'ida, is that he had the "intention" of launching such an attack, security sources said.

President Bush announced yesterday that a "full-scale manhunt" was under way across the United States for accomplices of Mr Muhajir. "We will run down every lead, every hint. We're in for a long struggle in this war on terror. And there are people that still want to harm America."