Royal Navy ship HMS Montrose seized Iranian weapons from speedboats being operated by smugglers in international waters south of Iran.
The Type 23 Frigate made the seizures whilst on routine maritime security operations in early 2022.
This is the first time a British Naval warship has interdicted a vessel carrying such sophisticated weapons from Iran.
The weapons seized included surface-to-air missiles and engines for land-attack cruise missiles, in contravention of UN Security Council resolution 2216 (2015).
The seizures, on 28 January and 25 February 2022, took place in the early hours of the morning.
HMS Montrose's Wildcat helicopter, equipped with state-of-the-art radar systems, was scanning for vessels smuggling illicit goods.
The helicopter crew spotted small vessels moving at speed away from the Iranian coast.
During the February interdiction, the US Navy destroyer USS Gridley supported efforts by deploying a Seahawk helicopter to provide critical overwatch during the operation.
On both occasions, the Wildcat helicopter pursued the vessels and reported back to HMS Montrose that they could see suspicious cargo on deck.
A team of Royal Marines approached the vessels on two Rigid Hulled Inflatable Boats before securing and searching the vessel.
Dozens of packages containing advanced weaponry were discovered, confiscated and brought back to HMS Montrose.
Armed Forces Minister James Heappey said: "The UK is committed to upholding international law, from standing up to aggression in Europe to interdicting illegal shipments of weaponry that perpetuates instability in the Middle East.
"The UK will continue to work in support of an enduring peace in Yemen and is committed to international maritime security so that commercial shipping can transit safely without threat of disruption."
The seized packages were returned to the UK for technical analysis which revealed that the shipment contained multiple rocket engines for the Iranian-produced 351 land-attack cruise missile and a batch of 358 surface-to-air missiles.
The 351 is a cruise missile with a range of 1,000km. It is regularly used by the Houthis to strike targets in the Kingdom of Saudi Arabia and was also the type of weapon used to attack Abu Dhabi on 17 January 2022, which killed three civilians.
The UK retains a permanent presence in the Middle East, with HMS Montrose having been deployed to the region since early 2019, actively supporting multinational maritime security operations and protecting the interests of the UK and its allies.
The ship operates under the control and direction of the UK Maritime Component Command (UKMCC), based in Bahrain.