The bill ratified by Majlis on November 27 was approved by the Guardian Council (GC) one day later.
The bill obliges the country’s Foreign Ministry to expel the UK ambassador within two weeks and reduce diplomatic ties with the British government to the level of chargé d’affaires.
The president is required to inform the country’s executive bodies of the law within five days after being notified by Majlis Speaker.
The motion to downgrade ties with London was first presented to the Majlis National Security and Foreign Policy Committee in 2009, following Briton’s interference in post-election unrest in Iran.
The bill was revived in response to Britain’s hostile approach towards Iran and the sanctions imposed by London against the country’s banking system and energy sector in coordination with the US and Canada.