LONDON—Britain’s Royal Navy has launched an investigation into the circumstances that led a state-of-the-art nuclear submarine to crash into a commercial vessel off the coast of Gibraltar.

Shortly after lunchtime on Wednesday, HMS Ambush, the Royal Navy’s most advanced hunter-killer submarine, was “involved in a glancing collision” with the merchant ship, said the Ministry of Defence late Wednesday.

HMS Ambush was submerged at the time, the ministry said.

Photographs of the submarine taken in the aftermath showed dents to the conning tower. The ministry said that while the submarine had sustained some external damage, the nuclear reactor used to power the ship wasn’t affected. The merchant vessel that HMS Ambush collided with appeared to be undamaged and none of the submarine’s crew were hurt, according to the ministry.

Spain’s foreign ministry said in a statement that it had requested “urgent explanations” and details from the British Embassy in Madrid about the collision. Spain has claimed the British overseas territory of Gibraltar for three centuries.

The 7,400 ton Astute-class submarine, which is capable of firing a nuclear-tipped missile, was towed to port in Gibraltar, where further checks are being carried out. The vessel was built by BAE Systems.

The news comes days after U.K. lawmakers voted to upgrade the country’s nuclear-armed submarine fleet. Replacing the country’s four warhead-carrying submarines will cost at least £31 billion ($41 billion) over 35 years.

Wednesday’s collision isn’t the first problem to befall HMS Ambush. In April 2013, the submarine was forced to return to base at Faslane, Scotland because of a mechanical problem.

Other British nuclear submarines have suffered serious mishaps. HMS Tireless, a Trafalgar-class submarine, limped to Gibraltar in 2000 after developing a leak in its nuclear reactor’s primary cooling circuit. Forced to undertake repairs at the British Overseas Territory, the length of time it spent in Gibraltar led to a diplomatic standoff with Spain due to fears of radioactive contamination.

Author: Alexis Flynn

Source: www.wsj.com