The West is approaching the point where it will have to decide whether to accept a nuclear-armed Iran or launch military strikes to disable its nuclear facilities, a leading international affairs think tank is warning.
The International Institute for Strategic Studies (IISS) said 2014 could be the "year of reckoning" for Tehran if it continues with its nuclear programme in defiance of world opinion.
In its annual review of world affairs, the IISS said Iran had already stockpiled sufficient low-enriched uranium to build up to six bombs once it had been highly enriched.
While Israel had so far accepted American warnings that a premature military strike on Iran would be counter productive, the IISS said that time for a diplomatic solution could be running out.
"So far, even with a highly unsatisfactory diplomatic process, Iran's hand has been stayed to a sufficient degree that the oft-threatened 'military option' to retard and temporarily disable Iran's capacity has not had to be urgently contemplated," it said. "However, the growing consensus is that 2014 could well be the year of reckoning, assuming that Iran continues to stockpile enriched uranium and make predicted advances in other areas."
The review said that it was possible that sanctions could result in a "demonstrable slowing down" in the nuclear programme, easing the international pressure, or that new President Hassan Rouhani could adopt a negotiating stance that leads to a "modus vivendi". "But it is equally possible that the binary choice between a military strike and acceptance of a nuclear Iran will have to be confronted."
The review also warned of the growing danger of a nuclear conflict breaking out between India and Pakistan as the result of a "miscalculation" between the two nuclear-armed rivals. It said there was a "high risk" of a renewed crisis if terrorist groups based in Pakistan mounted fresh strikes over the border into India. The Indian government would find it difficult to accept the Pakistani authorities were not involved and could retaliate by deploying troops into Pakistan. The Pakistanis, with significantly weaker conventional forces, could in turn retaliate with battlefield nuclear weapons.
The review said that Pakistan had already carried out three tests of the Hatf-9 solid-fuelled artillery rocket, which has a range of 60 km and is said to have been designed for use as a tactical nuclear weapon.
While Indian military doctrine would be to respond with "massive nuclear retaliation", the Pakistanis calculate that as such a weapon would have a relatively low nuclear yield India would have "neither the justification nor the political will" for such an overwhelming reaction.
"This doctrinal mismatch is clearly a recipe for instability, especially in a climate of volatile nationalism," the review said. "Accordingly, there is increasing cause for concern about a nuclear conflict resulting from miscalculation."