Midway through John Pilger's latest work, the globe-spanning writer and film-maker joins the annual Famine Walk organised by Action from Ireland (AFrI), retracing the 10-mile trek across Co Mayo in March 1849 made by hundreds of starving Irish. In a neat, acerbic chapter in which Pilger capsizes revisionist notions that the disaster was anything other than the result of a prevailing economic orthodoxy, he sets a historical context for his contemporary portraits: the repression of the powerless by rapacious, exploitative elites and their attendant ideologies.

John Pilger was born in wartime Sydney, his boyhood culture a curious Anglo-Saxon anomaly. Australia then saw itself as a "new Britannia", an Anglo-Irish outpost of empire transplanted on to a vast and faraway island-continent, with its convict-descended population uneasily reticent about its recent past.

In the chapters here, "Secret Waters" and "Anzac Day", he writes of a culture trying to ape that of its imperial masters, always supplying troops for wars which had nothing to do with Australia, and deleting from its memory the slaughter of the Aboriginals or its epic struggles in the cause of women's emancipation or workers' rights.

Pilger was part of the great post-war migration of Australians north. Arriving in "Swinging London", he recounts with genuine fondness being taken on board the pre-Maxwell Daily Mirror, then edited by Hugh Cudlipp. In the section entitled "The Rise and Fall of Popular Journalism", he argues against the claim that the pre-Murdoch "crusading" tabloid was a dinosaur, dispensing staid "worthy" copy, and out of touch with what working-class Britain wanted.

The Murdoch-built Sun in the 1970s aspired to the values of the approaching Thatcher decade: vulgar, populist and reactionary.

Murdoch, in his Wapping-led campaign against Fleet Street and the "militants" of the print unions, presented himself as an avenger against "elitism" on behalf of "the ordinary punter". In much the same way, he now rails against the "establishment" BBC in his endeavours to expand Sky TV and News International.

In the chapter "A Cultural Chernobyl", Pilger describes how valiantly the Sun championed "the ordinary punter" when, in the aftermath of the 1989 Hills borough stadium disaster, editor Kelvin McKenzie presented what Pilger claims was a wholly false account of Liverpool fans spitting and urinating on rescue workers or pick-pocketing the dead and injured. The resulting boycott by the Merseyside working-class was near unanimous and, on Murdoch's order, McKenzie sought to account for his actions on BBC Radio 4, where his "sarf London" accent became suddenly gentrified. In the media age, the rebellion against the "elite" has always been led by individuals whose true attitude to established power is one of fawning, vicarious adoration.

Elsewhere in Pilger's book there are accounts of the struggle for freedom against the murderous juntas of Burma and Indonesia. Pilger was the first western journalist to expose western complicity in the genocide committed in East Timor. He pays tribute to the Nobel-prize winning activists Jose Ramos-Horta and Bishop Belo, and four British women jailed for vandalising a British Aerospace Hawk fighter bound for Indonesia.

In South Africa, he finds the struggle for black emancipation in danger of being eclipsed by a new apartheid of rich and poor. In Vietnam, he travels to Hanoi with a paraplegic ex-US Marine and finds a city awaiting the embrace of foreign multinationals, Coca-Cola and MTV prevailing where the B-52 bomber failed.

This book may be a crucial testament of our times. In an age when mass technology promotes greater "choice" but less variety, when the struggle of the ordinary for justice is written out of political discourse, Pilger refuses to defer to consensus, offering an alternative view of the world.

Tom Farrell is a writer and critic