A new BBC One drama will explore the complexities around a suspicious death onboard one of the Royal Navy's submarines while on patrol providing the UK nuclear deterrence.
In Vigil, a six-part mystery starring Suranne Jones, the death is initially written off as accidental. However, Police Detective Amy Silva (Jones) suspects foul play and is taken aboard to investigate. The catch? The UK's nuclear deterrent must remain unbroken.
Vigil is from the producers of Line of Duty and Bodyguard and arrives on our television screens this Sunday night with an element of expectation.
This is strictly fiction but back in 2011, murder rocked the submarine fleet.
Murder In The Control Room
Lt Cdr Ian Molyneux was 36 when he was shot in the control room of the nuclear submarine HMS Astute. The victim, a father of four, had served in the Royal Navy for 20 years.
The killer, 22-year-old Able Seaman Ryan Samuel Donovan, also seriously injured another officer when he went on a violent rampage with his SA80 assault rifle.
At the time, the submarine was docked in Southampton on a special visit to the city.
Donovan's attack on 8 April 2011 came during a VIP visit to the sub, including local dignitaries.
The killer fired six shots, four of which missed their targets - other Royal Navy personnel present on the submarine. Donovan's attack could have continued were it not for the fast-thinking, heroic actions of local council leader Royston Smith, who wrestled Donovan to the ground.
During the trial at Winchester Crown Court in September 2011, the judge described Donovan's actions as a "murderous onslaught". The horrific events on Astute that day were described earlier in the proceedings by prosecutor Nigel Lickley QC. He said:
"Lt Cdr Molyneux reacted to the noise of the shots. As he turned to tackle the defendant he was shot in the head at very close range and died instantly. That was shot five. The defendant stepped over the body of Lt Cdr Molyneux and continued his progress towards the control room."
The reasons behind Donovan's crime may have lain in his previous poor discipline, for which he was being blocked from joining the Royal Fleet Auxiliary Ship Cardigan Bay. However, the court heard that the killer told a colleague he was trying to "create a massacre in the control room" a year earlier.
Donovan was assigned the weapon he used to murder Lt Cdr Ian Molyneux at 3 am that day as he awoke and reported for guard duty. Although the able seaman had been drinking the previous night, he passed a sobriety test and was deemed fit for duty.
Passing sentence, Mr Justice Field said that "in killing that officer, you robbed him of a bright future within a loving family".
"Your murderous onslaught was only brought to an end by the intervention of two civilians. There is no doubt their intervention prevented further deaths and serious injury."
Donovan was jailed for life on 19 September 2011. He must serve at least 25 years before being considered for parole.
The 12 December Serial Killer
The HMS Astute case was not the only killing at sea.
Allan Grimson was a Royal Navy Petty Officer who killed two men on the same 12 December date a year apart, in 1997 and 1998.
Grimson is suspected of killing more men, which could include the murders of 20 undiscovered victims.
The killer had served aboard HMS illustrious and was an instructor of fire fighting techniques. He joined the military in 1978.
Grimson's known victims were Nicholas Wright, an 18-year-old Royal Navy sailor and Sion Jenkins, a 20-year-old former recruit working as a barman in Portsmouth.
Grimson later admitted that Wright had refused to have sex with him, causing him to fly into a rage. He then hit the teenager over the head with a baseball bat and slit his throat in a bathtub. More than a year on from the event, while under questioning by police, Grimson also admitted being responsible for the disappearance of Sion Jenkins. He had murdered his other victim precisely one year to the day from killing Wright.
According to reports at the time, Grimson told police that he sought out the best-looking recruits, hoping to entice them into situations where he could dominate and then kill them.
He told police that killing Wright was "such a good feeling," adding, "I have never had that feeling. It was a feeling of power, a good feeling. Better than sex."
After admitting to the murders, Grimson led police to the bodies. Both had lain undiscovered near main roads since the murders.
Grimson's killings chime with that of a former soldier and notorious murderer, Dennis Nilsen.
Due to his tendency to kill on the same date, detectives suspected Grimson of being behind other attacks, too, most notably the 1986 disappearance of Royal Navy rating Simon Parkes.
Parkes was serving on HMS illustrious while docked in Gibraltar when he vanished on 12 December. Witnesses placed the two men together on the night Parkes went missing.
The unsolved case has led to multiple digs by British detectives hoping to find Parkes's remains and evidence to convict the 18-year-old's murderer.
During the most recent dig, police removed 80 tonnes of earth from The Rock's Trafalgar Cemetery and conducted lengthy DNA analysis on materials.
In 2001, psychiatrists were divided over the mental state of Grimson at the time of his killings. The eventual consensus among doctors was that the petty officer could stand trial. He was found guilty on two counts of murder.
Mr Justice Cresswell told Grimson:
"You are a serial killer in nature if not in number. You are a highly dangerous serial killer who killed two young men in horrifying circumstances."
Judge Cresswell sentenced Grimson to a minimum of 22 years but recommended he never be released. His minimum tariff was increased by the home secretary to 25 years but later decreased again to the original sentence due to the time he spent on remand ahead of trial.
Grimson will be eligible for parole later this year.
Vigil begins on BBC One on Sunday at 9 pm. The second episode will air on Monday, with the remaining four programmes airing on the following Sundays throughout September.
Cover picture: BBC.