However, Russian scientists at the site have raised grave concerns over Iran's apparent disregard for nuclear safety issues. Lobbying Kremlin directly, they have called for postponement of activation until at least the end of the year, to allow proper assessment of the damage caused to plant's computer operations by Stuxnet.

Meanwhile, the Iranian government remains bitterly opposed to any further delay, which it considers as another blow to national pride on a project that is running over a decade behind schedule. While according to western intelligence officials, Iran's nuclear programme is aimed at producing nuclear weapons, Iran maintains project's goals are peaceful.

 According to the Russian scientists' report to the Kremlin, a copy of which was accessed by the The Daily Telegraph newspaper, despite "performing simple, basic tests" on the Bushehr reactor, the Russian team "cannot guarantee safe activation of the reactor".

The scientists also accuse the Iranian management team, which is acting under heavy political pressure to stick to the deadline, of "not exhibiting the professional and moral responsibility" that is normally required. Accusing the Iranians of having "disregard for human life" they warn that Russia could find itself blamed for "another Chernobyl" if it allowed Bushehr to go ahead.

The New York Times reported yesterday that the Stuxnet virus had been developed as a joint project by US and Israeli intelligence officials at Israel's top-secret Dimona project in the Negev desert.

In what is now regarded as the most successful cyber attack in the world, the virus developed at Dimona over a two year period was planted into Iran's nuclear programme.

According to Hillary Clinton, the US secretary of state, the Stuxnet virus had set Iran's nuclear programme back by several years.

The Chernobyl disaster which is considered the worst ecological disaster in history, happened in April 1986 at a nuclear power plant in Ukraine. Following an explosion and fire in the facility, a plume of radioactive material was dispersed into the atmosphere which spread over an extensive area.