The war correspondent and writer Martha Gellhorn (1908-1998), who reported on conflicts from the Spanish Civil War to the Vietnam War, has been commemorated with an English Heritage blue plaque today (3 September).

The blue plaque marks the distinctive Victorian red brick building on Cadogan Square in south west London, where the journalist spent the last 28 years of her life and where she entertained friends and admirers from the worlds of literature and journalism. With this "sparsely furnished" top floor flat as her base, she continued writing and reporting into the 1990s, consolidating her reputation as a pioneering war correspondent and paving the way for future female journalists.

Journalist and Broadcaster John Simpson, said: "Martha Gellhorn would probably have said she didn't want a blue plaque outside her flat, but in fact I think she'd have been really pleased.

"This place is important because it's where she dispensed wisdom, sharpness of understanding – and Famous Grouse whisky – to generations of writers and journalists who came here to learn from one of the most perceptive observers of her time."

Author Victoria Glendinning, said: "It is wonderful to be associated with the unveiling of a blue plaque for Martha Gellhorn, a woman who was afraid of nothing and nobody. Though she held her convictions with passion, she had no self-conceit and would I think be amazed by today's celebration."

Though her glamour and her stormy marriage to Ernest Hemingway undoubtedly contributed to her fame, Martha Gellhorn made her name writing about ordinary people living under the adversity of war. Born in Saint Louis, Missouri, her career took off in 1934 when she covered the effects of the American Depression and in a clear and simple style, expressed her fury at the treatment of the poor, weak and dispossessed. Three years later, she reported on the Spanish Civil War and as a partisan journalist – Gellhorn always expressed disdain for objectivity – firmly supported the Republican cause.

Gellhorn fought for her place in the male bastion of war reporting in the early twentieth century and is remembered as an indomitable correspondent. During the Second World War, and circumventing the American military’s restrictions on female war correspondents, she stowed away on a hospital ship, an act that allowed her to report first-hand on the Allied invasion of France in 1944. Gellhorn spent the rest of the war ducking and dodging from front to front, filing articles as she could. Among her works of fiction is The Wine of Astonishment (1948), her response to Dachau and her visit to the concentration camp shortly after its liberation.

In 1996, twenty years after covering her last conflict, Gellhorn’s vehement opposition to the Vietnam War saw her return to the theatre of war and she penned a number of articles about the devastating effects on civilians. Extremely fit and active for almost all of her life, Gellhorn was latterly incapacitated by cancer and near blindness and in February 1998 she took her own life at her London home. Today at this same flat, English Heritage remembered and celebrated this remarkable woman.

The English Heritage London Blue Plaques scheme is generously supported by David Pearl and members of the public.