Britain has not sent any representatives to Tehran, a British source said after Iranian media reported that a mediator had been sent to discuss the freeing of a British-flagged tanker seized by Iran.
"We are not aware of any representatives being sent as mediators to Iran," a British diplomatic source said.
The UK is in a tense standoff with Tehran over British authorities' seizure of an Iranian tanker in early July and Iran's detention of a UK-flagged ship in the Gulf last week.
Wednesday’s denial came as Iran's President Hassan Rouhani said Tehran is ready for "just" negotiations but not if they mean surrender.
Rouhani seemed to be referring to possible negotiations with the United States.
US President Donald Trump withdrew from a landmark 2015 nuclear deal with Iran last year and reimposed sanctions on it, but has said he is willing to hold talks with Tehran.
"As long as I have the responsibility for the executive duties of the country, we are completely ready for just, legal and honest negotiations to solve the problems," Rouhani said, according to his official website.
"But at the same time we are not ready to sit at the table of surrender under the name of negotiations."
Amid soaring tensions in the region, Trump said in late June that he had called off strikes against Iran at the last minute in response to the destruction of a US drone.
A series of attacks on oil tankers in the Gulf region, as well as Iran's seizure of a British-flagged tanker in retaliation for Britain impounding one of its own vessels in Gibraltar, have turned the area into a powder keg.
