The group takes its name from the date in 1973 when 20 students were killed by riot police and soldiers, who suppressed the occupation of Athens Polytechnic on the orders of the colonels of Greece's military junta.
The group says it is a Marxist-Leninist organisation, virulently anti-American, anti-Nato and anti-capitalist. Its statements frequently criticise Greek politicians for failing to pursue nationalist issues.
In 1990 the Greek government launched a crackdown, which conspicuously failed to disrupt the terrorists' activities. But police last year did arrest George Balafas, one of the country's most wanted men, and said they had evidence linking him to the murder of the CIA's Athens station chief, Richard Welch, in 1975; Balafas's fingerprints were found on the keys to the car used in the shooting. His arrest was greeted with a wave of bomb attacks.
Earlier this month November 17 attempted to attack the aircraft carrier HMS Ark Royal when it docked in Piraeus for maintenance work before returning to help to enforce the UN economic embargo on Serbia, but a rocket launcher failed to fire.
George Kassimeris, a political researcher at Reading University, says that, though the organisation's small size limits the numbers of attacks it can carry out, it provides a defence against infiltration. 'A Greek expert working for the security services said no other terrorists operating today - not the Provisional IRA or ETA ,or any of the Palestinian factions - have demonstrated such extraordinary resistance to infiltration.'
MI6 and the CIA regard Athens as important, because of its proximity to the Middle East. It was described as Europe's 'soft underbelly' in the 1980s when several Arab terrorist groups launched operations from bases in Greece.
Greece's failure to curb the activities of November 17 has prompted Western security agencies, particularly the Americans who have suffered several casualties, to resume covert action.
This has already caused embarrassment. The US ambassador to Greece was recently forced to apologise publicly after two US diplomats were arrested by police in Athens in a van that contained guns and explosives.