Joshua, 12, made his own TV appeal for bone marrow donors

Joshua Hartley, 12, of Romsey, Hampshire, will be admitted into Great Ormond Street Hospital for pre-transplant chemotherapy on Thursday.

He and his brothers Nathan, 10, Daniel, eight, and Luke, four, have the rare degenerative condition XLP.

Their mother, Allison, was found to be a marrow match with Joshua in March.

Mrs Hartley is to donate her bone marrow to her eldest son

He is due to undergo the main transplant operation on 9 June after beginning nine days of chemotherapy on Bank Holiday Monday.

Without a successful transplant the boys, who are among just 100 people to have the disease, are not expected to live beyond their teens.

The boys' father, Dave, said: "It's felt like a long time waiting to get into the position where Josh goes up to Great Ormond Street, so we're really pleased that he's ready and willing."

If the operation is successful, it will be a complete cure for Joshua's illness, which affects his immune system.

A match has also been found for eight-year-old Daniel, but the family are still looking for donors for the other two boys.

More than 16,000 people have so far come forward offering to become donors, since the boys' illnesses became public two months ago.