MADRID: Thirty years after he put his life on the line to infiltrate the Basque separatist organization ETA, Mikel Lejarza is convinced that part of the Spanish secret service did not want the terror organization to be defeated.

Lejarza - possibly not his real name - claims security agents considered that ETA was a useful ally in their attempt to prevent the democratization of Spain following the death of dictator Fracisco Franco in 1975.

As a 25-year-old artisan, married and a father with money problems, Lejarza decided in the early 1970s to cooperate with the Franco-era authorities - becoming the only person thought to have penetrated ETA's highest command.

The information he gave was invaluable, leading to the capture of dozens of leaders and ETA foot-soldiers and preventing a mass Basque breakout from prison in Seville.

Lejarza's story came into the open this week, with the screening of a tense TV thriller about his exploits - paradoxically at a time when ETA appears to have been critically weakened and six of its former leaders, now in jail, have urged it to disarm.

Lejarza received the code name "El Lobo" - the wolf - when he plunged into the dark recesses of an organization that has killed more than 800 people in its bid for independence from Spain.

Lejarza said that just when he offered a plan to dismantle the entire organization, the secret services dropped him in 1975 after he had been two years undercover, in daily fear for his life. He said in interviews this week that this is when he realized that some officials did not want the organization to disappear.

But he says he continued to collaborate with Spanish intelligence in other capacities, and had worked abroad. With an ETA death threat hanging over him, he changed his appearance with plastic surgery. "I do not think that ETA knows who I am," he said. "I go to the Basque country like anyone else. Once, I crossed paths with my parents and they did not recognize me."

The Franco-Spanish film is directed by Miguel Courtois, a French basque, and stars Patrick Bruel, a French heartthrob singer, speaking impeccable Spanish, as the ETA commander. Lejarza's task was to penetrate into ETA's upper reaches without attracting suspicion, and without directly getting involved in crimes and attacks. -AFP