As de facto leader of The Beatles, he was one of the most famous people on the planet, and he used his celebrity status to stage a series of so-called "bed-ins" to promote peace.

Today, if a rock star tried protesting against wars and violence from a succession of luxury hotel bedrooms they would probably be greeted with howls of derision, but 40 years ago nobody had done anything like it before.

It was during one of these bed-ins, in Montreal, that Lennon and his wife Yoko Ono recorded Give Peace A Chance. The song was the first solo single released by a member of The Beatles while they were still together, and among the unlikely bedfellows whose voices can be heard on the record are Allen Ginsberg, Petula Clark and cartoonist Al Capp.

But rather than just becoming another musical oddity, the song rang out in the streets a few months later when more than half a million people demonstrated in Washington DC against the Vietnam War. Since then it has become a famous anthem sung at peace rallies and anti-war demonstrations all over the world. The 1960s, of course, were a hotbed of political and social protest, and as the civil rights movement continued its struggle for racial equality and the Vietnam War raged, songs like Bob Dylan's Blowin' in the Wind and Marvin Gaye's What's Going On? reflected the mood of the times.

Years earlier, songs like We Shall Overcome and (What Did I Do to Be So) Black and Blue sung by Louis Armstrong had shown that music was a powerful way of giving voice to the oppressed.

The baton was picked up by popular folk singers like Woody Guthrie and Pete Seeger, who have become synonymous with protest movements. But are peace anthems and protest songs now quaint historical artefacts?

Simon Warner, a senior music lecturer at Leeds University, believes they no longer have the galvanising effect they used to. "I think protest songs are far less prevalent than they were in the '60s and '70s. When the civil rights and anti-war demonstrations were going on and later when the punk movement was enjoying its period of dominance, songs were readily used as a vehicle of protest but that has ebbed away in recent years," he says.

"During the Aldermaston marches in the 1950s jazz songs were played and then a few years later folk music became the principle means of protest, through people like Joan Baez and Bob Dylan.

"By the end of the '60s, rock music had taken over and you had Jimi Hendrix playing his version of the Star-Spangled Banner, which raised all sorts of questions about what he thought it was to be an American. John Lennon also wrote a string of songs during this period that had a strong political message."

The unprecedented success of Do They Know It's Christmas?, Band Aid's 1984 charity single to raise money for famine relief in Africa, captured the public's imagination but in recent years people appear to have grown tired of tub-thumping musicians. So does this explain the dearth of modern protest songs, or do people no longer believe that songs are an effective form of protest?

"It could be argued that the early part of this decade offered plenty of opportunity for artists to make political protests, and there were some artists who came out and voiced anti-Bush sentiments," says Warner. "But if you look at the wars in Afghanistan and Iraq, musicians didn't get on their political soapbox and speak out in the same way as they did against the Vietnam War."

There have certainly been no shortage of high-profile protests since the turn of the century. On the eve of the Iraq War six years ago, more than a million people marched through the streets of London in protest, while the Make Poverty History campaign in 2005 saw hundreds of thousands of people pour onto the streets in Edinburgh. However, the lack of a rallying anthem on both occasions was deafening.

Those artists still compelled to write protest songs these days tend to be veterans like Neil Young, Billy Bragg and Bruce Springsteen. There are some exceptions, such as Radiohead, whose song You and Whose Army? expressed the band's anger and disappointment with Tony Blair's government, but they are few and far between.

Maybe, as Warner suggests, technology has had a more profound impact on society than we appreciate. "At one time, Karl Marx said religion was the opiate of the people, and perhaps now the electronic media has become the new opiate of young people, and they are more interested in its attractions rather than the notion of active protest.