AMERICA'S immigrant workers already have a cause and, as a wave of mass street protests continues to grow, seemingly unstoppable momentum. Now, if they want it, they also have an anthem: a Spanish-language version of 'The Star Spangled Banner', whose release on a small indie label has stirred outrage among white conservatives.

The record, produced by British music impresario Adam Kidron, features a Live Aid-style line-up of Latino artists including Wyclef Jean from Haiti, Gloria Trevi from Mexico, and Don Omar, Carlos Ponce and Olga Tanon from Puerto Rico. Together with the rapper Pitbull, they sing the US anthem in a Spanish translation under the title 'Nuestro Himno', or 'Our Anthem'.

The recording came together in just a few days in sessions spanning New York, Miami, Los Angeles, Puerto Rico, Mexico City and Madrid.

The Miami session coincided with the Billboard Latin Music Conference last week.

The idea, according to Kidron, was to make a statement of solidarity with the immigrant movement at the very moment that the issue is due to be debated . . . for the second time in a month . . . by the US Senate and hundreds of thousands of people are expected to return to the streets for a May Day protest and work boycott.

"I said, what's a song we could record that everyone could rally around?" Kidron told the Miami Herald. "Me and everyone I know are living the American dream and, to an extent, we do it on the backs of immigrants. I wanted to make the most beautiful version of the national anthem ever so it reflected the brilliance of these Latino artists, and, in a way, it is a gift to their people."

The recording shows every sign of being a publicity coup for Kidron's label, Urban Box Office, which specialises in reggaeton and urban Latino music. It has also stirred indignation from America's antiimmigrant lobby, which regards the translation of the national hymn as close to blasphemy.

One conservative commentator, Michelle Malkin, saw the recording as one more sign that Mexico intended to reconquer the US. Others worried that the Pledge of Allegiance might be next. Others still penned their own ditties, essentially telling the surging population of both legal and illegal Latino immigrants to go home.

The back-and-forth has been a microcosm of the larger immigration debate, in which demands for greater workplace protections and a road map to residency and citizenship for hard-working foreigners have been counterbalanced by demands for greater border militarisation and the arrest of the estimated 12 million illegal immigrants in the US.

The street protests began in reaction to a bill passed in the House of Representatives which would have branded illegal immigrants as felons.

Earlier this month, the Senate came close to passing a more liberal bill that would have recognised the fact that America needs immigrant labour and made provisions to provide it more honestly and securely.

Officials in Los Angeles are expecting at least 500,000 people to participate in a May Day march. In many cities, restaurants with immigrant staff are likely to stay closed.