A nurse infected with Ebola while working in Sierra Leone has said she is "happy to be alive" as she left hospital after making a full recovery.

Pauline Cafferkey is now free of the deadly virus after more than three weeks in a specialist isolation unit, where for a time she was critically ill.

She admitted she still felt "quite weak", but said she was looking forward to going home.

She also thanked staff at the Royal Free Hospital in London, whom she credited with saving her life.

Ms Cafferkey was diagnosed with Ebola after returning to Glasgow and was initially admitted to the city's Gartnavel Hospital on 29 December, before being transferred to the Royal Free the following day.

The nurse, from Cambuslang in South Lanarkshire, had volunteered with Save The Children at the Ebola Treatment Centre in Kerry Town before returning to the UK.

Ms Cafferkey, who was discharged from hospital on Saturday, said: "I am just happy to be alive. I still don't feel 100%, I feel quite weak, but I'm looking forward to going home.

"I want to say a big thank you to the staff who treated me - they were amazing. They were always very reassuring and I knew I was in the best hands.

"They saved my life."

Ms Cafferkey was treated in the hospital's high level isolation unit (HLIU) for more than three weeks.

She said listening to music and having "lots of Irn-Bru" had helped in her recovery.

While in hospital she was under the care of the infectious diseases team, led by Dr Michael Jacobs.

He said: "We are delighted that Pauline has recovered and is now well enough to go home. I am very proud of the staff who have been caring for her.

"It is because of the skill and hard work of the entire team that she is now able to go home."

Save The Children has launched an investigation into how Ms Cafferkey was infected, but admits it may never establish the exact circumstances.

Health Secretary Jeremy Hunt said: "I am delighted that Pauline Cafferkey has been discharged from hospital and can now return home.

"Her selflessness and courage are remarkable and she represents the very best of NHS values.

"I would like to thank all the staff at the Royal Free who have worked tirelessly to provide her with world class care and treatment."

Prime Minister David Cameron added: "It's great to see Pauline Cafferkey looking so well after her battle with Ebola. She's been extraordinarily brave."