William McNeilly, 25, went on the run after alleging the Trident missile programme, based on the Clyde, was a “disaster waiting to happen”.
Able Seaman McNeilly, from Belfast, wrote an online report detailing “serious security and safety breaches”. The MoD said Mr McNeilly was “apprehended” by Royal Navy police at Edinburgh Airport on Monday night and was being held at a military establishment in Scotland.
On Monday, a post on a Facebook profile apparently belonging to Mr McNeilly said: “I will be handing myself into the police today.”
Mr McNeilly’s brother, Aaron, told friends on Facebook this morning that he was feeling “happy” and said “my brother is safe and well”. He later added that his brother was in Scotland and said he had handed himself in.
An official investigation was launched after Mr McNeilly raised his safety concerns in an internet post. The navy said the fleet operated “under the most stringent safety regime”.
Mr McNeilly said he was an engineering technician submariner who was on patrol with HMS Victorious this year.
Victorious is one of the four submarines based at Faslane armed with the Trident missile system, Britain’s nuclear deterrent. Mr McNeilly’s 18-page report – The Secret Nuclear Threat – detailed what he claims are serious security and safety breaches aboard the vessel.
Incidents included in his report varied from complaints about food hygiene to failures in testing whether missiles could be safely launched or not.
He described security passes and bags going unchecked at the Faslane base, alarms being muted “to avoid listening” to them, and stories of fires starting in missile compartments.
Mr McNeilly said he raised these and other concerns through the chain of command on multiple occasions, but that “not once did someone even attempt to make a change”.
He insisted that he had been careful about the information he chose to release to avoid prejudicing security.
Speaking to the BBC, Mr McNeilly said he was “not hiding from arrest”. He said prison would be “such a nice reward for sacrificing everything to warn the public”.
He added: “Unfortunately that’s the world we live in. I know it’s a hard road to walk down, but other people need to start coming forward.
“Now I have no career, no money, no freedom, no chance of spending quality time with my family and friends. But I also have no regrets. There is no better feeling than truly serving the people.”
On Monday, a post on a Facebook profile apparently belonging to Mr McNeilly said he had “moved between countries, changed location almost every day”, but now “lacks the resources to remain undetected”.
A navy spokesman said: “The Royal Navy takes security and nuclear safety extremely seriously and we are fully investigating both the issue of the unauthorised release of this document and its contents. Submarines do not go to sea unless they are completely safe.”
The spokesman also said the navy “completely disagreed” with Mr McNeilly’s report, claiming that it “contains a number of unsubstantiated personal views, made by a very junior sailor”.