The announcement came just a day after Iran's new envoy to Britain, Hassan Habibollah-Zadeh, held talks in London on his first visit since his appointment last month, which ended a two-year freeze in diplomatic relations.
"Through the efforts of Iranian security forces, an MI6 spy has been arrested," the head of the Kerman revolutionary court, Dadkhoda Salari, said, referring to Britain's foreign intelligence service
"He has met British intelligence officers in person 11 times, both inside the country and abroad, and provided them with intelligence," Salari said.
He said the suspect had confessed to his crimes and was now being tried.
Salari gave no details as to the suspect's nationality or identity.
Britain shut its Tehran embassy after it was badly damaged in November 2011 by students protesting against Western sanctions imposed to put pressure on Iran to rein in its controversial nuclear programme.
But relations have improved since President Hassan Rouhani took office in August and Iran signed a landmark deal with major powers last month aimed at allaying concerns over its nuclear ambitions.
In November, Iran and Britain each named a non-resident charge d'affaires -- a diplomatic post that is one level below ambassador.
Iran's charge held talks in London on Friday, reciprocating a visit to Tehran by his British counterpart Ajay Sharma last week.
