After years of crucial Agency involvement with Iran, that country is closer to acquiring nuclear weapons than ever before,” it said.

CRITICISM

The 142-page report, entitled “Unleashing the Nuclear Watchdog”, was based on a two-year research project and was published by the Centre for International Governance Innovation.

It gave a largely positive assessment of the IAEA’s work, but criticised its initial handling of Japan’s Fukushima nuclear crisis last year, the worst accident of its kind in a quarter of a century.

“For 24 hours the IAEA said nothing publicly. It apparently saw no need for an early public assessment of the situation, an urgent meeting of member states or even a press conference,” it said, adding that the agency’s image had been “tarnished” by its reaction.

The IAEA and its Japanese director general, Yukiya Amano, defended the agency’s performance during the crisis, saying it was forced to rely on information from Tokyo.

Japan’s reactor meltdowns -- triggered by a deadly earthquake and tsunami on March 11 last year -- shook the world, raising questions about the safety of nuclear energy.

However, the IAEA still expects global use of nuclear energy to rise by up to 100 percent in the next two decades.

That is expected to place the agency and its inspectors under further strain, as some of the material and equipment used in a civil nuclear energy programme can - technically - also be diverted to develop nuclear weapons.