“We have had nearly two days of detailed, substantive talks focusing on the Iranian nuclear programme and the need for Iran to comply with international obligations,” said Ashton.

“The countries I represent are united in seeking a resolution of the international community’s concerns regarding Iran’s nuclear programme, which is the central purpose of these talks.

“We recognise Iran’s rights, but insist it fulfils its obligations.”

Ashton represented the five permanent powers of the Security Council — Britain, China, France, Russia and the United States, plus Germany at the meeting with Iran in Geneva.