The Royal Navy has launched an investigation after the Astute-class submarine was involved in a "glancing collision" with a merchant vessel.

The Ministry of Defence has confirmed that an investigation is now underway after one of its nuclear submarines collided with a merchant vessel.

The Astute-class HMS Ambush was involved in a training exercise off the coast of Gibraltar when the incident happened. It was submerged at the time.

The submarine has now docked at the British territory.

No crew were injured in the incident, although the submarine did suffer some “external damage”.

HMS Ambush’s nuclear reactor was not affected as a result of the collision.

Photographs of HMS Ambush arriving in Gibraltar show damage to the submarine’s coining tower.

In a statement, the Ministry of Defence said the collision happened at approximately 1330 local time on 20 July.

“HMS AMBUSH, an Astute-class submarine, while submerged and conducting a training exercise was involved in a glancing collision with a merchant vessel off the coast of Gibraltar. We are in contact with the merchant vessel and initial indications are that it has not sustained damage,” said the Ministry of Defence.

“The submarine suffered some external damage but there is absolutely no damage to her nuclear plant and no member of the ship’s company was injured in the incident,” it continued.

“An immediate investigation is being conducted.”

“The submarine will be entering Gibraltar later this evening (20 July) for further checks. There are no safety concerns associated with HMS AMBUSH being alongside,” concluded the statement.

According to the Royal Navy website, the Astute-class are the “largest, most advanced and most powerful attack submarines ever operated by the Royal Navy”.

HMS Ambush is one of the UK’s newest nuclear submarines.

Based at HMNB Clyde in Scotland, it was launched on 5 January 2011 and commissioned in March 2013.

Following trials around the UK, HMS Ambush was deployed to the Atlantic, calling in at Rio de Janeiro and Georgia in the USA.

According to the Royal Navy, “Ambush provides a formidable tool at the cutting edge of the UK’s military capability.”