The Royal Navy’s Trident missile-equipped nuclear submarine suffered a massive failure that sent the ship into an endless dive – engineers rescued the 140 crew members just before they were crushed by underwater pressure.

A Royal Navy submarine equipped with Trident nuclear missiles has reportedly suffered a massive failure, causing the ship to sink into the depths.

The Vanguard-class submarine had 140 crew members on board when its sonar suddenly failed during a deployment in the Atlantic Ocean.

A heated argument ensued in which the engineers managed to stop the submarine and the nuclear reactor from sinking further shortly before the disaster.

The deep-sea ship with Trident 2 missiles was on patrol when its depth indicators stopped working. The crew mistakenly believed it was flat, when in fact it was deeper in the ocean.

Only when engineers found a second indicator on the submarine’s stern indicating that they were heading for the “danger zone” did they sound the alarm.

Vanguard submarines can carry 192 nuclear warheads, but are currently limited to 48

“It’s not the engineers’ job to check the depth of the submarine, but they saw how deep they were and realized something was wrong,” a source told The Sun.

“The submarine was technically still at a depth we know it can operate at, but should it ever go that deep, the entire crew will be diverted to operational stations.

“It did not happen. The submarine should not have been there and was still diving. And if it continued like that, you wouldn’t really have to think about it anymore.”

Although it is not known what depth the submarine reached, the maximum operational depth of this type of ship is about 500 meters, according to Military Today.

The incident prompted an immediate investigation, insiders told the newspaper, adding that it had no impact on Britain’s nuclear deterrent.

It is unknown which of the four Vanguard-class nuclear submarines were involved in the gruesome ordeal.

The force’s four ships – HMS Vanguard, Vengeance, Victorious and Vigilant – each displace 15,900 tonnes underwater and are more than 149 meters long.

Since 1969, at least one Royal Navy submarine has patrolled with nuclear missiles in case of a surprise attack

However, only two of the ships are currently in use, one is being converted and another is undergoing sea trials.

Since 1969, at least one Royal Navy submarine has patrolled with nuclear missiles in case of a surprise attack.

Vanguard submarines can carry 192 nuclear warheads, but are currently limited to 48.

A Royal Navy spokesman said: “Our submarines continue to fulfill their obligations, operating around the world, protecting national interests and keeping us and our allies safe.”

“While we do not comment on specific details of the submarine operation, the safety of our personnel is always our top priority.”