Britain reopened its embassy in Tehran on Sunday 23 August, a striking signal of how Western ties with Iran have thawed since protesters stormed the compound nearly four years ago. Foreign Secretary Philip Hammond held a news conference with his Iranian counterpart Mohammad Javad Zarif.

"Iran is an important power in the region and it is in everybody's interest that Iran is engaged in the region as a responsible actor in favour of regional stability," Hammond said.

The top British diplomat urged patience with the process. "Lets walk first and try to run later," Hammond said adding that "we will have to overcome a deficit of trust."

Zarif said Iran needed to set aside old approaches and engage with all its neighbours. "We believe that exclusion should not be the practice in our region, we believe that all of us face the same challenges, all of us have similar opportunities to improve the living standards of the people of this region, all of the people of this region, "Zarif said. "We need to start cooperating based on non-zero gain strategy, based on mutual gains, because if we try to gain at the expense of others all of us will lose...We call upon our neighbours in this region to respond positively to this approach by Iran," Zarif said.

During Hammond's stay in Tehran, the British foreign secretary is due to hold talks with Iranian President Hassan Rouhani and other officials. It will be the first visit to Iran by a British foreign secretary since 2003.