Britain said on Monday it had revived diplomatic relations with Iran and appointed a non-resident charge d'affaires, two years after an angry mob ransacked the British embassy in Tehran.
The announcement reflects a thaw in relations with the West and comes after Iran and six world powers, including Britain, came close to a preliminary agreement about Tehran's nuclear programme at the weekend.
Britain's Foreign Office said Ajay Sharma, currently the head of the ministry's Iran department, will take up the post immediately.
More top news
Two people have died and a hundred buildings have burned down following a wildfire in California.
Adam Pritchard was visiting family in Iowa, USA, when he appeared to fall from his bike and later died.
A four-year-old boy is among 20 people to have died in some of the worst flooding West Virginia has seen.