Since his award-winning 1989 debut feature Roger & Me, a scathing account of the closure of the General Motors plant in his hometown of Flint, Michigan, documentary filmmaker Michael Moore has been gleefully raising the hackles of the political establishment.

The Big One poked merciless fun at the glossy image of corporate America while Bowling For Columbine pulled few punches in its critique of America's gun culture, winning Moore an Oscar into the bargain.

Most recently, Moore launched a blistering attack on the Bush administration and its role in the September 11 tragedy with the provocative and timely Fahrenheit 9/11.

Manipulative, irreverent and unapologetically in your face, the acerbic writer-director shamelessly pushes his agenda, equally interested in raising his own profile as highlighting a particular social concern.

With his new feature Sicko, the filmmaker turns his attention to America's healthcare crisis, tracing his country's decline since Richard Nixon's televised address on February 18, 1971, when he proclaimed: I want every American to have the finest healthcare in the world and I want every American to be able to have that care when he needs it.'' From its sombre opening Moore makes clear his disdain for a system where people literally have to pay to live.

Some of the real-life horror stories that follow are laced with mordant humour, like Rick who lost two fingers in an accident and had to decide between re-attaching his middle finger at a cost of 60,000 dollars or his ring finger at a cost of just 12,000 dollars.

Many of the people Moore interviews share heartbreaking tales designed to have us sobbing in sympathy, like the Ground Zero rescue worker with severe respiratory problems, who pays hundreds of dollars every month for her inhaler medication.

Travelling to Cuba, the film discovers that the very same medication costs the equivalent of about five cents.

As usual, Moore bends the truth, or at least shows only what enforces his argument, like the rose-tinted footage of a British hospital where the patients are delighted with the service and the doctor leads a charmed life free of stress or financial burden.

A subsequent visit to France further shames America's healthcare system.

Sicko promotes Moore's viewpoint with flair and scathing wit, ridiculing Bush and the current administration, bombarding the screen with damning headlines and horrific accounts of neglect.

It is fascinating and utterly engrossing, as long as you take this generous spoonful of cinematic medicine with a generous pinch of salt.