Iran agreed a deal “in principle” at talks in Geneva to ship the majority of its low-enriched uranium overseas for reprocessing into nuclear fuel that could be used for a medical research reactor.

A deal outlining this was finalised in Vienna this week and a deadline of midnight tonight was set for the agreement to be sealed with Tehran.

The framework deal, along with an offer to allow international inspectors into its newly-revealed enrichment plant at Qom, was hailed as evidence that Iran was responding positively to the diplomatic track.

Today, however, with just hours until the deadline, Iran has turned the table on its foreign interlocutors with a rival proposal, demanding that it be allowed to buy higher enriched uranium directly from abroad.