A second warship has arrived in the Strait of Hormuz to protect British ships in the strategic waterway, as the foreign secretary urged Iran to “come out of the dark” and release a British-flagged tanker it detained there two weeks ago.

The Ministry of Defence said that Royal Navy vessel HMS Duncan arrived over the weekend and will work with frigate HMS Montrose in accompanying merchant vessels to “secure this essential route”.

Iran has previously slammed the move as “provocative”, criticising a wider British proposal to create a European-led naval mission to escort tankers in the Gulf.

In a veiled threat on Monday, the Iranian Revolutionary Guard Corps (IRGC) then released a recording it claimed showed its troops warning a British warship not to interfere during its 19 July seizure of British-flagged Stena Impero.

Dominic Raab, the foreign secretary, urged Iran to follow international rules and release the vessel, which together with its crew, remains under the control of the guards.

“You cannot go about detaining unlawfully foreign vessels,” he told Sky News on Monday.

In photos: British-flagged tanker seized by Iran Show all 13 1 /13 In photos: British-flagged tanker seized by Iran In photos: British-flagged tanker seized by Iran A speedboat of Iran's Revolutionary Guard moving around the British-flagged oil tanker Stena Impero Tasnim News Agency/AP In photos: British-flagged tanker seized by Iran Crew members of the British-flagged tanker Stena Impero, that was seized by Iran in the Strait of Hormuz EPA/IRIB News Agency In photos: British-flagged tanker seized by Iran A satellite image of the Iranian port city of Bandar Abbas reveals the presence of the seized British oil tanker, the Stena Impero on July 22 Maxar Technologies/Reuters In photos: British-flagged tanker seized by Iran Iranian Revolutionary Guard Corps (IRGC) claims to have seized Stena Impero at the Strait of Hormuz with 23 crew on board on 20 July EPA/IRIB News Agency In photos: British-flagged tanker seized by Iran Iranian Revolutionary Guards patrolling around the captured British-flagged tanker Stena Impero as it's anchored off the Iranian port city of Bandar Abbas AFP/Getty In photos: British-flagged tanker seized by Iran epa07733612 A handout photo made available by Iranian state-run IRIB News Agency on 22 July 2019 shows crew members of the British-flagged tanker Stena Impero, that was seized by Iran in the Strait of Hormuz on 19 July 2019. Iranian Revolutionary Guard Corps (IRGC) claims to have seized Stena Impero at the Strait of Hormuz with 23 crew on board on 20 July 2019. EPA/IRIB NEWS AGENCY / HANDOUT HANDOUT EDITORIAL USE ONLY/NO SALES IRIB NEWS AGENCY / HANDOUT EPA/IRIB News Agency In photos: British-flagged tanker seized by Iran A satellite image of the Iranian port city of Bandar Abbas reveals the presence of the seized British oil tanker, the Stena Impero on July 22 Maxar Technologies/Reuters In photos: British-flagged tanker seized by Iran A speedboat of the Iran's Revolutionary Guard moves around a British-flagged oil tanker Stena Impero AP In photos: British-flagged tanker seized by Iran epa07733614 A handout photo made available by Iranian state-run IRIB News Agency on 22 July 2019 shows crew members of the British-flagged tanker Stena Impero, that was seized by Iran in the Strait of Hormuz on 19 July 2019. Iranian Revolutionary Guard Corps (IRGC) claims to have seized Stena Impero at the Strait of Hormuz with 23 crew on board on 20 July 2019. EPA/IRIB NEWS AGENCY / HANDOUT HANDOUT EDITORIAL USE ONLY/NO SALES IRIB NEWS AGENCY / HANDOUT EPA/IRIB News Agency In photos: British-flagged tanker seized by Iran In this photo released by state-run IRIB News Agency, which aired on Monday, July 22, 2019, shows cooks in the galley of the British-flagged tanker Stena Impero that was seized by Tehran in the Strait of Hormuz on Friday. The Associated Press cannot independently verify the condition of the crew members, but in the video they looked to be in good health and it didn't appear as though they were being filmed under duress. (IRIB News Agency via AP) AP In photos: British-flagged tanker seized by Iran epa07733619 A handout photo made available by Iranian state-run IRIB News Agency on 22 July 2019 shows crew members of the British-flagged tanker Stena Impero, that was seized by Iran in the Strait of Hormuz on 19 July 2019. Iranian Revolutionary Guard Corps (IRGC) claims to have seized Stena Impero at the Strait of Hormuz with 23 crew on board on 20 July 2019. EPA/IRIB NEWS AGENCY / HANDOUT HANDOUT EDITORIAL USE ONLY/NO SALES IRIB NEWS AGENCY / HANDOUT EPA/IRIB News Agency In photos: British-flagged tanker seized by Iran epa07733613 A handout photo made available by Iranian state-run IRIB News Agency on 22 July 2019 shows crew members of the British-flagged tanker Stena Impero, that was seized by Iran in the Strait of Hormuz on 19 July 2019. Iranian Revolutionary Guard Corps (IRGC) claims to have seized Stena Impero at the Strait of Hormuz with 23 crew on board on 20 July 2019. EPA/IRIB NEWS AGENCY / HANDOUT HANDOUT EDITORIAL USE ONLY/NO SALES IRIB NEWS AGENCY / HANDOUT EPA/IRIB News Agency In photos: British-flagged tanker seized by Iran epa07733616 A handout photo made available by Iranian state-run IRIB News Agency on 22 July 2019 shows crew members of the British-flagged tanker Stena Impero, that was seized by Iran in the Strait of Hormuz on 19 July 2019. Iranian Revolutionary Guard Corps (IRGC) claims to have seized Stena Impero at the Strait of Hormuz with 23 crew on board on 20 July 2019. EPA/IRIB NEWS AGENCY / HANDOUT HANDOUT EDITORIAL USE ONLY/NO SALES IRIB NEWS AGENCY / HANDOUT EPA/IRIB News Agency

“If the Iranians want to come of the dark and be accepted as a responsible member of the international community they need to adhere to rules-based system of the international community,” he added.

According to Tom Trent, the commanding officer of HMS Duncan, it had to be relocated from an “intense deployment” in the Mediterranean and Black Sea, where it had been supporting a French carrier strike group with live operations in Syria.

The Type 45 destroyer will work with HMS Montrose until it comes off duty in late August.

Tehran is furious with Britain and European powers for failing to protect it from renewed sanctions imposed by the United States after Washington withdrew from a nuclear agreement between Iran and world powers.

Under the 2015 deal, international sanctions on Iran were relaxed in exchange for Tehran curbing its nuclear programme.

But tensions reached breaking point after the dramatic detention of the Stena Impero on 19 July, which many believed was retaliation for the earlier seizure near Gibraltar by the Royal Marines of Iranian oil tanker Grace 1, which was suspected of breaking EU sanctions.

After the 4 July incident, Tehran threatened to capture a British oil tanker, and a fortnight later detained the Stena Impero, claiming it was “violating international maritime rules”.

Mr Raab said in another interview on Monday that the seizure of these ships was not equivalent and ruled out an exchange of vessels.

“Grace 1 was intercepted because it was in breach of sanctions and heading with oil for Syria and that was the intelligence,” he told the BBC.

“We were absolutely lawfully entitled to detain it in the way we did. The Stena Impero was unlawfully detained. This is not about some kind of barter. This is about the international law and the rules of the international legal system being upheld and that is what we will insist on.”

There was no confirmation or denial from the UK authorities of the audio and video released by the Iranians on Monday, which they said showed their forces warning off a British warship.

“You are required not to interfere in these issues,” the IRGC navy representative can be heard saying, in the clip posted by semi-official news agency Tasnim.

“This is British warship foxtrot two three six. I am in the vicinity of an internationally recognised strait with a merchant vessel in my vicinity conducting transit passage,” a voice with a British accent replies.

“Don’t put your life in danger,” the navy representative adds.

The video also contains an exchange between the IRGC and the same British warship during a stand-off in mid-July involving the British Heritage oil tanker, according to Tasnim.

Three Iranian vessels attempted to block the passage of the British Heritage through the Strait of Hormuz but withdrew after warnings from a British warship, the British government said on 11 July.

Defence secretary Ben Wallace said on Sunday that the UK authorities were working to scale down the tensions.

The HMS Duncan Type 45 destroyer (Getty) (Photo by Jeff J Mitchell/Getty Images))

“While we continue to push for a diplomatic resolution that will make this possible again without military accompaniment, the Royal Navy will continue to provide a safeguard for UK vessels until this is the reality.”

However, the secretary of Iran’s Expediency Council has said that Iran will not let the United States and the United Kingdom take control of the Strait of Hormuz.

“Americans and Britons have been constantly flaring up tensions in the region and recently they did so in the Persian Gulf, pretending that they have control over the Strait of Hormuz and vessel movements there. We will definitely not allow this to happen,” Mohsen Rezaei said, according to the conservative Mehr news agency.