Britain and other European nations are at risk from Iranian terror attacks on home soil and must do more to deter the regime, America’s counter-terrorism coordinator has warned.

Nathan Sales said in an interview with The Daily Telegraph that Iran has carried out a slew of assassination plots in Europe in recent years and could do so again.

He praised the UK government for recently designating Hezbollah, the Shia Islamist group backed by Iran, as a terrorist organisation and urged other EU countries to match the move.

Mr Sales also pointed the expulsion of Iranian ambassadors from European countries in the early 1990s after a bomb attack, saying that playbook could be “instructive” for dealing with today’s threat.

“It is unacceptable that Iran would regard the European continent as fertile ground for its campaign of terrorism,” Mr Sales warned.