Six-year-old Danni Clifford, from the remote British dependency of St Helena, arrived in the early hours of the morning in Cape Town after a four-day trip by cargo ship.

She had collapsed with a suspected rare and potentially fatal blood disorder, aplastic anaemia.

Danni in the arms of a doctor on her arrival in South Africa

She needed specialist treatment but St Helena, which lies 1,200 miles west of Angola and has a population of just 5,500, does not have an airport and the island's next ship was not due to visit for three weeks.

So doctors on the island asked British coastguards in Falmouth, Cornwall, to broadcast an SOS.

The Nomzi, a 20,000 tonne container ship which had been en route to Cape Town from North Carolina in the US, backtracked 300 miles to pick up its emergency cargo.

Captain Peter Wierling said she had to be transported over large waves to board the ship and was kept in isolation on board to protect her from infection.

'Tired and resting'

She was taken straight to a private clinic, where doctors performed tests to confirm her diagnosis.

A spokeswoman for the Constantiaberg Medi-Clinic, where Danni is being treated, said on Saturday she was "tired and resting", and waiting for her parents.

John and Cheri Clifford were due to arrive 24 hours after Danni from the Falklands Islands, where they had been doing contract work.

St Helena: Remote island best known as the last home of Napolean

Ursula Johnson, the children's grandmother who accompanied Danni with a nurse on the journey, said: "We are keeping our fingers crossed."

The results of additional tests on Danni will be announced on Monday.

If she has aplastic anaemia, the illness could be cured with a bone marrow transplant from her eight-year-old brother Reece, or sister Teri-Sue, nine, who also accompanied her on her journey.

St Helena is best known as the site of Napoleon's final exile, from 1815 until his death in 1821.

These days its residents eke out a living on fish exports and ship maintenance.