A Royal Navy nuclear submarine was involved in a collision in the middle of the Atlantic, it was reported today.
The crash between HMS Vanguard and French submarine Le Triomphant, which was also carrying nuclear warheads, is believed to have occurred on 3 or 4 February, The Sun newspaper claimed.
Despite being equipped with sonar to detect other vessels, neither submarine apparently realised the other was in the same part of the ocean.
A senior Navy source told the newspaper the potential consequences of such a collision were "unthinkable".
He said: "It's very unlikely there would have been a nuclear explosion. But a radioactive leak was a possibility. Worse, we could have the crew and warheads. That would have been a national disaster."
The Ministry of Defence (MoD) refused to confirm the incident had taken place, saying it was against its policy to comment on submarine operations.
However, a spokesman insisted nuclear security had not been breached.
He said: "We can confirm that the UK's deterrent capability has remained unaffected at all times and there has been no compromise to nuclear safety."
Inquiries are under way on both sides of the Channel.Reuse content