File photo: Reuters 

LONDON: Nine British sailors assigned to a nuclear submarine have been discharged from the Royal Navy after failing compulsory drug tests, Britain´s ministry of defence has confirmed.

The service personnel, stationed aboard HMS Vigilant -- one of four Royal Navy submarines equipped with nuclear missiles -- were dismissed after all tested positive for an illegal substance.

"We do not tolerate drugs misuse by service personnel," a Royal Navy spokesperson said.

"Those found to have fallen short of our high standards face being discharged from service."

The spokesperson also confirmed the navy had launched an investigation into other service personnel on HMS Vigilant over allegations of inappropriate relationships, detailed in British media reports this month.

"We can confirm an investigation is underway, but it would be inappropriate to comment further at this stage," the spokesperson added.

"Any allegations of wrongdoing are taken very seriously and will be dealt with appropriately."

HMS Vigilant is one of four Vanguard-class submarines in the British navy.

Each vessel is equipped with up to eight Trident missiles armed with nuclear warheads.