The vessel technically didn't break any international laws.
A Russian submarine had to be "chased" away from the Cork coast by the British Royal Navy.
The incident has come to light now, six months after it happened.
The vessel technically didn't break any international laws, as it was outside of the 12 mile limit, just south of Cork Harbour.
Security and Defence Analyst, Mullingar's Declan Power says Ireland is a weak spot to target Britain: