Britain has announced that it is stepping up its pressure on Iran.
New sanctions are being imposed, severing more economic ties with the country.
The move comes after a report from the UN’s nuclear watchdog said Tehran had worked on developing nuclear weapons and was possibly still doing so.
All UK financial institutions have been ordered to stop doing business with their Iranian counterparts, including the central bank.
However, the move is not thought to be targeting the oil trade.
Britain is coordinating sanctions with the US and Canada. Washington is expected to outline its plan of action later on Monday.
The new steps are aimed at preventing Tehran from using the international banking system to finance its nuclear programme.