William Hague calls Iran to discuss restoring diplomatic ties

The breakthrough phone call between Mr Hague and Ali Akbar Salehi, Iran's outgoing foreign minister, came after overtures from Tehran following last month's general election.

Mr Hague afterwards announced that he would meet with Iranian representatives at the United Nations General Assembly meeting in New York in September. The Iranian delegation in New York will be led by Hassan Rouhani, the Glasgow-educated new president who has said he wants to improve Iran's international ties.

A Foreign Office statement said Britain and Iran could explore improved ties in the face of the need for "urgent progress" to resolve the West's concerns about Iran's nuclear programme.

"The Foreign Secretary said he was willing to meet the Iranian Foreign Minister during the UN General Assembly in New York in September," the Foreign Office said. "He made clear that the UK was open to improvements in the bilateral relationship with Iran, on a step-by-step and reciprocal basis."

Mr Rouhani has said that he hoped for better ties with Britain when he takes over from President Mahmoud Ahmadinejad on Sunday. Britian closed its embassy in Tehran after it was overrun by a mob in November 2011. Mr Hague said there was level of government involvement in the attack and gave Iranian diplomats in the UK 48 hours to leave the country.

All eyes will be on who Mr Rouhani chooses as the next foreign ministers. Sources in Tehran said he was determined to nominate a moderate Western educated diplomat, Javed Zarif, a former ambassador to the United Nations as chief diplomat.

Britain is one of a number of countries seeking an agreement to halt Iran’s production of 20 percent enriched uranium — one processing step short of weapons-grade — and removing the stockpile of such medium- enriched uranium so that it can’t be diverted for weapons. If such a deal can be achieved, the way would be open for talks on UN sanctions that have sought to curtail Iran's nuclear ambitions.