By Mark Davies BBC News Online political reporter

It's unlikely that the stand-in singer of punk-inspired garage band The Bizzos ever really thought he'd end up singing with a real-live rock star.

Or indeed that David Wright, MP for Telford and former front man of the Swallowing Battalions of Camels - yes, really - would do the same.

One of the problems with Top of the Pops is there are too many S Club 7-types who went to stage school

Billy Bragg

But on Wednesday a few yards from Downing Street, those dreams came true as Mr Wright and Tom Watson, MP for West Bromwich East and ex-Bizzos singer, joined a parliamentary backing group for singer-songwriter Billy Bragg.

Snag

With them were Labour's Kevin Brennan - whose musical CV includes guitar, "fake piano" and vocalist with folk group Cadlan - and Pete Wishart, MP for Tayside North, who can claim real rock credibility as a former member of successful Scottish bands Runrig and Big Country.

Full flow: Bragg lets rip

Just one snag for the main event: they weren't actually allowed to join in as Bragg aptly banged out a version of the Crickets and Clash hit "I Fought the Law".

Indeed, they could have broken the law if they'd so much as hummed a couple of lines.

Instead, Bragg was accompanied only by Liberal Democrat MP David Heath as the backing group stood silently with their mouths tightly taped shut.

The event in the tiny basement bar of the Red Lion pub was part of a campaign to persuade ministers to scrap a law that makes live performances by more than two musicians illegal without a public entertainment licence.

Ban

Campaigners say even an EastEnders-style pub singalong is a criminal offence without such a licence - with landlords facing a maximum penalty of a �20,000 fine and six months in jail.

This law stifles entertainment and stifles opportunities for young and old coming forward to perform

David Wright MP

Hence the masking tape over the mouths of the MPs and a ban on foot-tapping, humming or dancing.

All very tongue in cheek, of course, but in aid of what campaigners say is an important issue if the stars of the future are not all to be manufactured by record companies.

Mr Heath, who has won backing from more than 185 MPs for the campaign, said the law - known by musicians as "the two-in-a-bar" rule - amounted to a "tax on music".

Ministers are believed to favour scrapping the law and replacing it in a package of licensing reforms in the Queen's Speech with proposals to allow singing in pubs where money does not change hands.

Soap operas

But the Musicians' Union, which organised the pub gig, says that would make matters worse, putting "grassroots music making under threat" by not allowing payment for young acts.

Gagged: MPs Watson, Brennan and Wright on the right side of the law

Billy Bragg told BBC News Online: "When I was starting out I played a lot of pubs, a lot of working men's clubs, students' unions.

"It was important because it gave me a chance to find out whether my songs actually meant anything. You can't tell that by playing a tennis racquet in your bedroom.

"One of the problems with Top of the Pops these days is there are too many S Club 7-types who went to stage school or who appeared in soap operas.

"It does nothing for the ordinary young people trying to make it. Playing in pubs is one way of beginning to get the confidence to do that."

Whizzkids

There is cross-party support for the campaign, with MPs urging the prime minister to remember his own foray into rock music with his Ugly Rumours band at Oxford University.

Safe outside: The MPs can join in

Tom Watson - who used to stand in as singer for The Bizzos, a Ramones cover band, when his friend was too drunk to perform - said there was a battle going on for the ear of Tony Blair with the Queen's Speech approaching.

"The real issue is about young people coming together to make music," he said. "So many venues have closed down.

"The music industry is very keen on computer whizzkids making songs in their bedrooms and they have taken their eye off the ball."

David Wright - he of the Swallowing Battalions of Camel, veterans of two concerts and a tape called Europe Slides Into World War Three (It sold about three copies, he says), agreed.

"At the moment this law stifles entertainment and stifles opportunities for young and old coming forward to perform," he said.

Starstruck

"It is part of our cultural heritage and if we are to do that effectively we need to see some change in this particular law."

After a brief performance in the Red Lion, Bragg and his backing group moved outside, where the MPs were allowed to remove the tape from their mouths and join the singalong without fear of law-breaking.

And it was hard to escape the feeling that for some there was an element of being just a little starstruck in the presence of Billy Bragg.

Tom Watson, for instance, admitted that he once went out and bought two copies of a new Bragg album - "in case he lost one on the bus home".

But seeing that The Bizzos didn't hit the big time, you can't really blame him for idolising someone who did.