Michael Moore, film-maker and scourge of the Bush administration, has been handed a timely gift of pre-release publicity for his new documentary, SiCKO, by the US treasury department which is investigating him for filming in Cuba in violation of a travel ban. A letter from the treasury posted on Moore's website asked him to explain how he came to be in Cuba in March without authorisation. Dated May 2, the letter requested information on his travel dates, a list of people who went with him and justification for his presence in Cuba in apparent contravention of the terms of the US embargo of the country imposed since 1962.

By deciding to investigate Moore, government officials seemed unaware that he has consistently thrived on such confrontation. His last film, Fahrenheit 9/11, hit the headlines in 2004 when Walt Disney refused to let its subsidiary Miramax release it because of its attack on the Bush administration. Miramax went ahead anyway, and the film took the top prize at Cannes, the Palme d'Or.
SiCKO does for the US health system what Fahrenheit 9/11 did for Mr Bush and Bowling for Columbine did for the American obsession with guns. It takes the drugs companies to task and relates the stories of people abandoned without health insurance.

The trip to Cuba has already garnered some controversy. Moore took with him 10 sick workers involved in the clear up of ground zero following the attacks on New York on September 11 2001. The sequence filmed there is understood to involve a comparison between the poor care that many of the workers have been offered in the US compared with the cutting-edge new treatments they were given free on the Cuban health service.

Last night a spokesman for Moore said news reports about his taking victims of the September 11 attacks to Cuba for health care were inaccurate. SiCKO has its world premiere at Cannes on May 19 and opens in the US on June 29.