Iran has signalled its intent to have the capability to make nuclear weapons, a Bradford University expert has warned.

Professor Paul Rogers, of the Peace Studies Department, said a recently-discovered facility in Iran was significant because it was underground.

He said: “If Iran was to withdraw from the non-proliferation treaty – it has to give three months’ notice and it would not be subject to inspections – and to put all its efforts into developing nuclear weapons, it would take about three years to develop an arsenal of around six deliverable weapons.”

Another option would be to make a basic device which was not viable as a weapon but proved Tehran had nuclear capability.

Prof Rogers said: “If it were to re-enrich its low-grade uranium to weapons-grade for an experimental device it would take about a year.

“That would almost be a demonstration to show it had the capability.

“From the point of view of the regime in Tehran it would be a signal that they are one of the big boys.”

However, he said that the uranium ore Iran used was contaminated with other heavy metals which would make it difficult to enrich.

He said: “It’s not clear that Iran has the domestic capability to produce weapons-grade uranium.

“As far as one can tell they want the ability to make the nuclear weapons but it doesn’t mean that they are actually doing it.”