The widow of skiffle king Lonnie Donegan has warned that the families of dead music stars could face financial hardship when royalty payments end.
Lonnie Donegan died in 2002
Performers in the UK receive payments from record sales and radio airplay for 50 years after a song is released.
But Sharon Donegan has called on MPs to extend the term, and bring it into line with songwriters and composers who get royalties for life, plus 70 years.
Donegan's 1957 hit Cumberland Gap goes out of copyright in January next year.
The musician, who died in 2002 aged 71, had his first hit in 1956 with Rock Island Line.
UK performers receive royalties from record sales and radio airplay for 50 years after a song is released
Songwriters get royalties for life and a further 70 years after their death
At the end of the 50 year term, the record company loses the exclusive rights to sell and distribute a recording
Material is protected for 95 years after it is published in the US
It went out of copyright at the end of last year for the performers and the record company, but the songwriter's family and his publisher still get royalties.
Writing in music magazine Music Week, Ms Donegan said: "Rock Island Line was a 1930s song, but Lonnie's recording was quite unlike the blues original. It was an up-tempo version, which just steamed along.
"I bet if you asked most people whose song it was, they would say Lonnie or Johnny Cash or one of the other singers who recorded it.
"It was their recording which brought the song to life and that's what people remember."
Sir Cliff Richard has also called for changes in the law
Ms Donegan said the royalties provided a much-needed income for her, and many others in a similar situation.
"His recordings of Rock Island Line and Cumberland Gap are effectively worthless once the copyright term ends," she said.
"It's not even as though they made us rich. People say I must be a millionaire, but, no. The royalties were just enough to get by."
Phonographic Performance Ltd (PPL), the UK broadcast royalties collection society, is releasing a limited edition CD for MPs called the Copyright Gap, a reference to Cumberland Gap's situation.
Ms Donegan hopes the CD - which also features tracks from Kirsty MacColl, The Beatles, The Who, The Kinks and Led Zeppelin - will help change the current copyright law.
She said: "I just hope the politicians listen to all the tracks on that CD and then give us the same copyright term as the songwriters and photographers.
"Hard-working people like Lonnie, who gave so many so much fun, deserve at least this."