Abu Dhabi CNN  — 

The British Heritage super tanker is owned by BP, under a British flag, and on charter to an Anglo-Dutch company, so it’s unsurprising that the ship appeared to abandon suddenly its plans over the weekend as it sailed within sight of Iran.

Anger in Iran had been growing over the seizure of one of its tankers by British commandos off the coast of Gibraltar last week, and the country’s military had threatened some kind of retribution.

So instead of loading up with 140,000 barrels of oil in the Iraqi port of Basra on Friday, the British Heritage instead steamed off empty to safe haven in a Saudi port, according to data from the tracking platform Marine Traffic.

On Wednesday, the tanker switched off its identifying beacon for almost 24 hours, perhaps trying to blend in amid the dozens of other vessels cluttering the Persian Gulf. It then picked up an escort from HMS Montrose, a British Type 23 Frigate, for a sprint through the Straits of Hormuz, unburdened by cargo.

The skipper’s instincts were dead on. According to sources in the British Ministry of Defence, the Montrose drove off three Iranian gunboats that sought to herd the tanker into Iranian waters in or near the Straits of Hormuz.

HMS Montrose manned its guns and leveled its 30-millimeter automatic cannon to add menace to the verbal warnings given to the Iranian ships to clear off.