A 55-year-old librarian who advertised on London buses for an egg donor in a desperate attempt to become a mother, gave birth to a baby girl this month after 14 years of trying to start a family.

Linda Weeks, from Maidstone, Kent, said no words could describe her gratitude to the woman who came forward to donate eggs and help her realise her dream of motherhood.

She said: “It is hard to think what words would be enough. ‘Thank you’ seems inadequate. We will be grateful for ever. She is fantastically generous. It is such a wonderful thing to do.”

Weeks, who will not meet the donor, added: “It would be wonderful to know what made her come forward, but we will never know.”

She and her husband, Richard, 50, a computer programmer, started trying to conceive more than 14 years ago, shortly after their marriage. They have spent more than £21,000 on fertility treatment and £2,000 on the ads they placed for a month on 50 buses across London.

Weeks, whose daughter, Katy, was born on June 3 weighing 5lb 11oz, said: “It was our final roll of the dice before we looked at adoption and fostering. I had to do it . . . if I didn’t, no one was going to come up and ask me if I wanted one of their eggs.”

The ads showed a photograph of the couple on their wedding day in March 1993, smiling and looking forward to having a life and family together. The ads begged for a young woman to donate her eggs to fulfil their wish to become parents.

Weeks had previously traipsed round newsagents, asking them to put adverts in their windows. Some were sympathetic; others refused. None of the ads yielded a suitable donor.

Weeks thought that if she had the chance to tell people a little more about herself, potential donors might be more sympathetic.

“Until then,” she said, “I had been a 52-year-old woman or a 53-year-old woman who wanted a baby. All people knew about me was my age, but you cannot tell anything from that.

“People might have thought that I was a career woman who now wanted it all or who thought I was entitled to children because I wanted them, or that I was selfish not to have had them before. I needed a poster so that people could read about us and how we got into this situation.”

It was the media coverage generated by the posters that prompted a donor to come forward. A total of 96 women initially expressed an interest in donating their eggs but, in the end, only one went ahead.

If Weeks had had to wait any longer it is unlikely that she would have found a British clinic to treat her, because of her age. Although there is no official age limit for IVF in Britain, doctors do not treat those over the age 55 and the NHS will not fund treatment for women over 39.

Britain’s oldest mother, Patricia Rashbrook, a child psychiatrist from Lewes, East Sussex, gave birth at the age of 62 in 2006 after treatment in Russia.

Weeks’s case, which high-lights the extreme difficulty of obtaining donor eggs, has renewed calls for donors to be paid. Dr Magdy Asaad, clinical director of the London Fertility Centre and the Logan Centre, where Weeks was treated, said sufficient numbers of women would not donate eggs unless they were given something in return.

He said women were forced to go abroad to countries such as Spain or America, where women can be paid for their eggs.

Asaad said: “At the moment women do not get paid anything except some expenses, to a maximum of £250 per cycle. That just covers their travel expenses, meals and so on but does not pay them for what they do.”

Asaad added that, although many women inquired about egg donation, they were put off when they realised that they would not be compensated.

“Once you explain to them about the treatment they have to go through,” he said, “then many of them turn away. They do not feel they are benefiting in any way.”

Weeks has decided to speak out about the joy she and her husband have found in their long-awaited daughter in an attempt to persuade more women to donate eggs. She said: “We would encourage them to contact their nearest clinic and find out what is involved. They could be giving a gift of life to another couple who would never have children otherwise.

“It is still hard to believe that Katy is really ours. It is just wonderful. It is the best news that we could ever have.”

Doctors say that, although there has always been a shortage of eggs and sperm, the problem was made worse by new legislation that came into force in April 2005, giving all children born after that date the right to trace their biological parents once they reach the age of 18.

They argue that the fear of genetic offspring knocking on their door has put many men and women off donating sperm and eggs.

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