The Basque separatist group ETA planned to set off a car bomb aboard British-bound ferry Val de Loire, but the activists in charge of the attack were reportedly captured by Spanish police last week.
It was reported that the ETA wanted to drive a car bomb onto the ferry, which was bound for Plymouth in southwestern Britain, and blow it up at its point of origin in the Spanish port at Santander.
The armed group allegedly ntended to give authorities a warning to allow the boat to be evacuated before the explosion.
A suspected ETA guerrilla who was captured last week tipped off police, saying that the ferry was a possible target. It was reported that a ferry schedule was found among the suspect's possessions but that it could not be confirmed whether there was a real threat to the boat.
Earlier this year, ETA warned tourists to stay away from Spain after setting off bombs at two resorts in an apparent attempt to hurt the country's huge tourism industry.