By Jonathan Duffy BBC News Online Magazine

Lock up your sons and daughters - public enemy number one in 1984

It was during his peak-time chart rundown one Wednesday morning in January 1984 that Radio 1 DJ Mike Read suddenly twigged.

While treating his listeners to a performance of Frankie Goes to Hollywood's thumping dance single Relax, Read idly scanned the record sleeve and began to read the lyrics to the song, which had been steadily climbing the charts.

Then, mid-broadcast, he lifted the needle, denounced the content as "obscene" and refused to play it again. The rest of the BBC followed suit, banning the song, with its veiled reference to gay sex, from all TV and radio airplay, with the curious exception of the top 40 show.

Within a fortnight the song had rocketed to number one, where it nested for four weeks. (As if to rub the Beeb's nose in it, a few months later Relax returned to the charts, reaching number two.)

They are an exciting, competent new band, but I just feel the lyrics are overtly obscene - after I took it [off air] many people came up to me and said they were really pleased I had done so DJ Mike Read in 1984

Relax was not the first song to be banned from the airwaves, nor the last, but, 20 years on, it was probably the most significant, says Martin Cloonan, author of Banned! Censorship of Popular Music in Britain, 1967-1992.

"It was the time when Radio 1 realised this couldn't go on anymore because they ended up looking so ridiculous," says Cloonan.

With every week the song remained in the top slot, its subversive status intensified. The blacklisting became an inadvertent gift to the Frankie stable, keenly exploited by the group's publicity team.

The group's name became a badge of youth rebellion; its "Frankie Say" T-shirts a political statement.

Wrong message

These days Radio 1 does not go in for banning records, says the station's editor of music policy, Alex Jones-Donelly.

"You can never say never, but today the concept of banning seems rather far-fetched."

Brasseye's treatment of paedophilia ran foul of the censor

Networks today are more savvy; blacklisting is likely to send out the wrong message.

"We need to reflect youthful culture in the UK. If we don't understand our audience then quite clearly they won't trust us," says Jones-Donelly.

So does anything go these days on the nation's top youth music station?

No. Instead there are a range of devices to help keep the audience on-side. "Heavy lyrical content" is consigned to non peak-time shows, says the Jones-Donelly, while words can be bleeped out, blanked out or played backwards.

Rap artists themselves often play along, releasing "clean" and sometimes "squeaky clean" edits to reach the biggest audiences.

The idea of "outraging" the public as a marketing device for pushing a product is outdated, says Radio's 1's policy man.

Political correctness

The lesson that censorship can be self-defeating extends beyond pop music, so are we living in a more permissive society than that 20 years ago?

The parameters of censorship are constantly changing Martin Cloonan 'Banned' Frankie tops chart

"That's a complete misconception," says Cloonan. "In sexual references things have loosened up, but political correctness has imposed a new restraint on free speech."

Cloonan points to the fall-out over Channel 4's Brass Eye, which poked fun at the media's handling of paedophilia. But it's a point that will resonate with many of those who back the BBC presenter Robert Kilroy-Silk, whose has been taken off air for his controversial remarks about Arabs.

And in music, today's battleground is over the homophobic lyrics of Jamaican reggae artists such as Beenie Man and Bounty Killer. Gay rights campaigner Peter Tatchell has led calls for police to investigate the artists.