A pioneering surgery used to restore hearing in adults who have lost the auditory nerve is now being used for deaf children born without it.

A little girl who was born profoundly deaf will be able to hear her parents sing happy birthday after becoming one of the youngest people in the UK to have pioneering hearing surgery.

Leia Armitage, who is four on Sunday, was born with a rare form of deafness.

She was missing her cochlea and auditory nerve in both ears - without these, it is impossible for sound to reach the brain.

She underwent pioneering brain surgery to have an auditory brainstem implant (ABI) two years ago and has just returned to St Thomas' Hospital in central London to have her final check-up where doctors confirmed the procedure has been a success.

The complexity of her condition means that it has taken time for her brain to adapt to be able to hear sound, and she is just learning to form her own speech.

The electronic hearing device stimulates neurons directly at the brainstem, bypassing the cochlea and auditory nerve entirely.

Leia, who lives with her mother Alison and father Bob in London, is now able to listen to and enjoy her favourite Disney films and is looking forward to the arrival of a little brother, who is due in September.

Mr Armitage, 42, a union rep at Royal Mail, said: "We were devastated when we found out Leia was missing her auditory nerve as well as her cochlea.

"We thought we had no hope as her deafness was so rare, but thanks to the ABI we've come so far.

"Leia can now hear us calling her from other rooms and we spend hours watching her dance and sing along to her favourite Disney films.

"We're so excited to sing Happy Birthday to her, it's going to be a special day for the whole family."

Mrs Armitage, 39, a training manager at Tesco, said: "It's been a long journey, but Leia is a little miracle. We're so grateful for the hard work and determination of everyone involved in her care.

"We want other parents in the same situation as us to know that there is another option out there for their child's hearing. There is hope."