Her voice is phenomenal - it's like a mixture of Aretha Franklin, Roberta Flack and the great soul singers

Tony Bramwell, Hot Records

Cassidy's father Hugh, who lives in Washington DC in the US, said he was astounded by the success.

But he added that he always knew his daughter's voice was special.

"Something in her voice resonated with people and grabbed them with the phrasing and dynamics and such," he said.

"She had this unerring pitch and this gift for harmony and picking up something quickly."

US artist Cassidy recorded a number of musical standards, including a rendition of Over The Rainbow, made famous by Judy Garland.

But Cassidy was passed over by major record labels and remained largely unnoticed before her death.

Eva died before her talent was recognised

Songbird was first released in 1998 and was picked up in the UK by Tony Bramwell, Hot Records.

He said: "Her voice is phenomenal. It's like a mixture of Aretha Franklin, Roberta Flack and the great soul singers."

He also introduced Paul Walters, producer of Terry Wogan's Radio 2 show, to her talent.

The song Over The Rainbow was then included on the presenter's playlist as a result.

Cassidy died four months after she was first diagnosed with cancer.

"We all had hopes of her recovering, but she passed away here in the home," her father said.