The travel bans and asset freezes coordinated with Washington are aimed at disrupting what London calls Tehran's "hostile activities in the UK and around the world".

They target the leader of the Islamic Revolutionary Guard Corps (IRGC) Quds Force and individuals linked to Iran's allies Hamas and Palestinian Islamic Jihad.

Britain has long designated both Palestinian groups as terrorist organisations.

The sanctions also include strengthening export restrictions on drone components, and new powers to impose transport sanctions on ships involved in contravening existing sanctions or controlled by sanctioned individuals.

"The behaviour of the Iranian regime poses an unacceptable threat to the UK and our partners," Foreign Secretary David Cameron said.

"It continues to threaten people on UK soil and uses its influence to destabilise the Middle East through its support to armed groups, including Hamas and Palestinian Islamic Jihad.

"The UK's new Iran sanctions regime gives us extensive new powers to tackle this appalling behaviour," he added, arguing it sent "a clear message to the regime we will hold you to account for your actions".

Alongside Washington, London unveiled the first set of designations under the new sanctions regime, naming IRGC head Esmail Qaani as one of those targeted.

A further seven individuals and one entity, all with links to Hamas and Palestinian Islamic Jihad, were also designated, the UK government said.

London accuses Iran of human rights abuses as well as stepping up efforts to kill or kidnap perceived enemies of its regime, including in Britain.

It says the Iranian intelligence services have developed close relationships with organised criminal gangs in the UK and across Europe to help target opponents.

The latest measures add to ones already imposed over Tehran's hardline response to protests that have rocked the Islamic republic since the September 2022 death in custody of Iranian-Kurdish woman Mahsa Amini.

The 22-year-old had been arrested for an alleged breach of strict dress rules for women.

The UK has targeted more than 350 Iranian individuals and organisations, including other leading IRGC commanders and Tehran's prosecutor general.

The US and the European Union have also toughened their own sanctions.