Junior Foreign Minister Alistair Burt travelled to Iran for talks with Tehran as European signatories to the nuclear deal try to keep it alive.
The deal relaxes economic sanctions on Iran in exchange of the country stopping its nuclear weapons development.
US President Donald Trump pulled out of the accord earlier this year, and slapped sanctions on the country.
State news agency IRNA quoted Iranian Foreign Minister Mohammad Javad Zarif as telling reporters: “It is time for the Europeans to act in addition to voicing their political commitment.
“These measures may be costly, but if countries want to reap benefits and if they believe the nuclear accord is an international achievement, they should be ready to keep these achievements.”
Mr Burt earlier met Iranian Deputy Foreign Minister Abbas Araghchi, Iran’s state television reported.
Mr Zarif said the talks with Burt had involved “access to banking resources and the sale of oil.”
Iran has been seeking commitment from European signatories of the nuclear deal that it will be able to access the Western banking system and continue to sell oil despite U.S. sanctions.
In a statement before his visit, Burt said: “As long as Iran meets its commitments under the deal, we remain committed to it as we believe it is the best way to ensure a safe, secure future for the region.”
Mr Zarif later spoke by telephone with his French counterpart Jean-Yves Le Drian, state media reported, saying they discussed bilateral ties, the nuclear deal and regional developments.
A day earlier, Iran dismissed a call by Mr Le Drian for negotiations on Tehran’s future nuclear plans, its ballistic missile arsenal and its role in wars in Syria and Yemen.
Mr Burt was also expected to discuss the cases of dual nationals detained in Iran.
He is expected to try to negotiate the release of Nazanin Zaghari-Ratcliffe, a project manager with the Thomson Reuters Foundation who was arrested in April 2016 at a Tehran airport as she headed back to Britain with her daughter, now aged four, after a family visit.
She was convicted of plotting to overthrow Iran’s clerical establishment, a charge denied by her family and the Foundation, a charity organisation that is independent of Thomson Reuters and operates independently of Reuters News.
Today her husband Richard Ratcliffe wrote an open letter to Iran’s foreign minister Javad Zarif, after she was temporarily freed this week.
Mr Ratcliffe said his wife was deeply upset at being forced back to prison after a three-day release, which he branded a “cruel game”.
Upon her return to prison she passed out during a panic attack and had to be taken to a prison clinic.
Accompanying Mr Burt in Tehran, London’s special envoy to Syria Martin Longden later met senior Iranian Foreign Ministry official Hosein Jaberi Ansari, IRNA reported.
IRNA said Longden had expressed concern about the future of Idlib and the possibility of the use of chemical weapons there.
The Syrian province of Idlib and surrounding areas are the last major enclave held by rebels opposed to Syrian President Bashar al-Assad, a close Iranian ally. A source has told Reuters Assad is preparing a phased offensive to regain the province.