She was born in 1912, daughter of Georgios Vlachos, a prominent royalist and the founder (in 1919) of Kathimerini, Greece's nearest equivalant to a newspaper of record. Although she wrote for the newspaper before the Second World War (inter alia she covered the 1936 Berlin Olympics), her journalistic reputation was made by her pithy political diary column under the byline "E", which was launched when Kathimerini resumed publication in 1945, after the end of the German occupation.
On the death of her father in 1951 Vlachos assumed control of Kathimerini, launching its afternoon stablemate, Mesimerini, in 1961. She was also the driving force behind Eikones, Greece's first mass-circulation illustrated magazine, and a pioneering cheap, but high quality, paperback imprint, Galaxias, many of whose volumes retain their value even 40 years later.
Under her ownership Kathimerini and Mesimerini offered steady, if not always uncritical, support for the Right in Greece. Vlachos's finest hour undoubtedly came with the establishment of the colonels' dictatorship in April 1967. She dealt the usurpers a crushing blow by immediately and without hesitation closing down her presses in protest against the coup and the ensuing censorship, thereby delivering a devastating blow to any hopes the junta may have entertained of co-opting elements of the constitutional Right in their support.
Although the presses were silent, Vlachos continued to hold court in the Kathimerini building in Socrates Street, in Athens, and to ridicule the pretensions of the military usurpers who proceeded to misgovern Greece by means at once brutal and absurd.
Her description (wholly deserved) of Brigadier Stylianos Pattakos as "a clown" and other outspoken criticisms of the regime led to her being placed under house arrest in October that year.
From this she made a daring escape in December 1967, a few days after King Constantine's abortive counter-coup. She dyed her hair with shoe polish and travelled on a false passport; her arrival in London was the occasion for a further blast of anti-junta publicity throughout the world.
Unlike the leading politician of the Right, Konstantinos Karamanlis, who, while making his distaste for the junta clear, for the most part chose while in exile to keep his own counsel during the seven years of the dictatorship, Helen Vlachos immediately immersed herself in a non- stop publicity campaign against the colonels, a struggle in which she was joined by two other redoubtable women opponents of the regime, Melina Mercouri, the actress, and Amalia Fleming, the Greek widow of the discoverer of penicillin, Sir Alexander Fleming.
This formidable troika proved more than a match for the buffoonish and self- important colonels. Vlachos's graphic account of life under the junta in the months before her escape, House Arrest, was published in 1970.
As editor in London of the Hellenic Review, a lively and well-informed emigre journal, she acquired a copy of a report sent by the colonels' PR man in London to his masters in Athens. The leaking of this document, which revealed, among other things, that a British Labour MP had been employed as a lobbyist, caused an immense furore. This not only ruined an important element in the colonels' expensive propaganda campaign but gave powerful impetus to the establishment of the Register of Members' Interests in the British Parliament.
Perhaps Vlachos's greatest service to the cause of democracy in Greece was as a broadcaster much in demand for her witty barbs, expressed in fluent and idiomatic English, against the junta. She was very well aware that for a British audience ridicule was a much more effective weapon than hyperbole.
On the downfall of the colonels' regime she returned to Athens and in 1974 restarted production of her newspapers. She was appointed a state deputy for the ruling New Democracy Party in the first democratically elected post-coup parliament. She also became president of the Association of Greek Newspaper Publishers.
In 1987 she sold Kathimerini to George Koskotas, the would-be newspaper and banking tycoon, whose business empire soon afterwards collapsed in a welter of scandal and corruption.
Vlachos's 60-year career as a journalist was wittily recounted in a multi- volume memoir, Dimosiographika Khronia: peninda kai kati . . . ("Journalistic Years. Fifty and more . . .") published in the early 1990s.
Eleni Vlachou (Helen Vlachos), publisher: born 18 December 1911; publisher, Kathimerini 1951-67, 1974-87; married 1935 Ioannis Arvanitides (marriage dissolved), 1951 Constantinos Loundras; died Athens 14 October 1995.