A fourth Royal Navy warship has been despatched by the UK for patrol duties in the Persian Gulf, in the wake of the capture of the Stena Impero and her 23 crew last month by Iranian commandos.

The Ministry of Defence confirmed Saturday night the destroyer HMS Defender is heading for the disputed region after the earlier deployment of HMS Duncan, HMS Kent and HMS Montrose.

The Portsmouth-based Type 45 destroyer Defender will protect UK ships amid heightened tensions in the Strait of Hormuz.

The move to enforce the Royal Navy presence comes just four days after Australia announced it will join the United States, the UK and Bahrain in an international maritime coalition protecting oil tankers and cargo ships from threats posed by Iran.

A series of attacks on merchant vessels in the past few months has disrupted shipping through the area, which the United States has blamed on Iran. Tehran has denied the accusations.

Tension in the region increased when the UK seized an Iranian oil tanker off Gibraltar last month, prompting Iran to retaliate by seizing a British tanker in the Persian Gulf.

The Ministry of Defence confirmed earlier this month that the Royal Navy has been tasked to accompany British-flagged ships through the Strait as part of the International Maritime Security Construct (IMSC).

Defence Secretary Ben Wallace said on Saturday night: “The men and women of HMS Defender will contribute to the IMSC alongside international partners.”