The British Foreign Office summoned Iranian charge d'Affaires in London on Sunday following overnight missile and drone attacks against Israel.
"The UK condemns in the strongest terms Iran's direct and unprecedented attack against Israel, as well as their violation of Jordan and Iraq's airspace," a Foreign Office spokesperson said in a statement.
The spokesperson noted that at a time of "great tension" in the Middle East, this was a "profoundly dangerous and unnecessary" escalation by Iran.
The UK also called for the immediate and unconditional release of the civilian ship MSC Aries and its crew, which was seized by Iranian armed forces in international waters on Saturday.
The statement said the Iranian authorities must take meaningful and immediate action to de-escalate and halt its what it called "reckless and unlawful behaviour."
"The UK will continue to stand up for Israel's security and the security of all our regional partners, including Jordan and Iraq," it added.
Iran's Islamic Revolutionary Guard Corps launched a barrage of drones and missiles at Israel late on Saturday in response to the April 1 attack on the Iranian consulate in Damascus that killed several Iranian commanders.
The IRGC is said to have fired more than 300 drones and missiles in an attack that lasted several hours, many of which were intercepted by Israeli air defense systems. The US and France also helped ward off the attack.
