Sharon Berger, the grandmother who launched an international hunt for a bone-marrow donor after being diagnosed with leukaemia, “leaves behind an inspirational legacy that will save lives,” say her family.

Mrs Berger, 65, succumbed to her illness last week after a five-year battle that united the community behind her search for a donor.

She passed away surrounded by family in Hammersmith Hospital where she was being treated.

Her son Jonni Berger said her family were “devastated” but were “taking strength from the huge number of people who have joined the stem cell register because of her campaign”.

In December 2012 Mrs Berger fell seriously ill with myelodysplastic syndrome (MDS), a malfunction of the bone marrow in producing blood cells, and underwent intensive chemotherapy in hospital while waiting for a transplant.

A donor was found following a four-month campaign known by its Twitter hashtag #Spit4Mum.

Many celebrities pledged their support on social media, including singer Britney Spears, Israeli model Bar Refaeli, One Direction member Liam Payne, singer Olly Murs, and comedian Eddie Izzard.

After a routine blood test in July 2016, Mrs Berger received the devastating news that her cancer had returned and started several weeks of chemotherapy.

Her son said: “It was a huge blow to the family. She had to have a second transplant and I was her donor but I was only a 50 per cent match.

“Although it extended her life, it didn’t cure the leukaemia.”

He added: “Tributes have poured in from around the world as well as from across the British Jewish community, including from the Reform, Liberal, United synagogue movements as well as from the communities of Stamford Hill. “The Spit4Mum campaign brought people together to save lives irrespective of their affiliation or denomination.”

Over 1,190 Jewish people joined the Anthony Nolan donor register in the first four weeks of the campaign and the number has grown significantly since.

Jewish areas in London now have the highest concentration of stem cells donors, as a result of the Spit4Mum campaign.

Henny Braund, Anthony Nolan’s chief executive, said: “Sharon spoke eloquently about her experiences of MDS and leukaemia, as well as the challenges she faced with her transplant. 

“It was a privilege to know and work with her. She will be sorely missed by all at Anthony Nolan.”

Mr Berger said: “I think her death leaves an inspirational legacy that will hopefully save lives.”

His mother, whose funeral at the Western cemetery in Cheshunt on Sunday was attended by hundreds of people, was lucid and communicating with her family right up to the end of her life.

Mr Berger said: “She was proud of what she had done, and worried about her family and wanted to know that we would all be OK.”

Before her death the grandmother-of-two — who was from north-west London and belonged to Finchley Reform Synagogue — was able to see her daughter Caroline get married in an intimate ceremony attended by immediate family.

Mr Berger said: “That was important to her and Caroline. She was able to come out of hospital and see it happen.”

Mrs Berger’s daughter in law, Rabbi Miriam Berger, of Finchley Reform Synagogue said: “As a community we are already seeing Sharon’s legacy live on.

“It was only a few weeks ago that a member of the shul in her twenties, who registered through the Spit4Mum campaign, donated her stem cells as an anonymous donor. While it doesn’t take away our sadness to have lost Sharon it does give us hope that others will have the gift of life.”

Rabbi Avraham Pinter, a prominent figure in the strictly Orthodox community of Stamford Hill said Mrs Berger “had a great zchus (merit) in getting so many people on to the bone marrow register.”