While earlier the hack was attributed to Russian hackers, The Time has reported citing intelligence assessments that the Iranians were behind the attack.
On Saturday, The Times newspaper reported citing intelligence assessment of the incident that Iran had carried out a cyber attack on British lawmakers earlier this year.
The news comes at a time when Britain has joined other countries, including the European Union, in warning the U.S. against harming the 2015 nuclear deal with Iran.
Earlier this year in June, the British parliament was hit by a “sustained and determined” cyber attack that was designed to identify weak email passwords; the attack came just after a month of the ransomware worm which crippled parts of the country’s health service.
The Times report states the attack was Iran’s first significant cyber attack on a British target.
The hack was initially blamed on Russia.
Britain’s National Cyber Security Centre was not immediately available for comment.
The Iranian government had no immediate comment.
Although the motive for the attack is yet to be established, The Times report states the hackers were not seeking just financial profit.