The barrister and wife of Prime Minister Tony Blair said: "I have lost contemporaries with young children and also my beloved Auntie Audrey to the disease.

Photographs: Linda McCartney

"When I was growing up in Liverpool, Auntie Audrey was an integral part of a large extended close-knit family. She was there at all the important milestones in my life.

"She was with us in the constituency in Trimdon, seeing the boys when she was taken ill and had to return home just a few days before she finally died of breast cancer.

"I don't know a woman who doesn't worry about finding a lump in her breast and my close contact with my aunt and her family taught me that, terrifying as that is, it is only the start of the cancer journey."

'Terrible disease'

Writing in the Daily Mail, she said she asked Sir Paul McCartney if he would help raise funds for Breast Cancer Care by agreeing to sell one of his wife's photographs.

Linda McCartney died from the disease exactly one year ago.

The proceeds raised from the sale of prints of the signed black and white picture - titled Stallion and Standing Stone - will go towards funding a Linda McCartney Breast Care Nurse.

Hundreds of letters

Mrs Blair says she was appalled that "this terrible disease should have claimed a woman as striking and charismatic as Linda in the prime of her life".

She had received hundreds of letters in which many women "admitted to the terrible anxieties that her death had triggered in them".