These are the first pictures from inside the operating theatre, supplied today by the Royal Children's Hospital. The delicate operation involves more than 16 surgeons and medical staff over a staggering 16 hours. Picture: Royal Children's Hospital

Neurosurgeon Wirginia Maixner is leading the 16-hour operation. Picture: RCH

First pictures from inside the operating theatre. Picture: Royal Children's Hospital

Plastic surgeons Andrew Greensmith and Tony Holmes. Picture: RCH

First pictures from inside the operating theatre at RCH. Picture: RCH

First pictures from inside the operating theatre. Picture: Royal Children's Hospital

Plastic surgeons Andrew Greensmith and Tony Holmes. Picture: RCH

Plastic surgeon Andrew Greensmith inside the operating theatre. Picture: RCH

Neurosurgeon Alison Wray. Picture: RCH

Anaesthetists Andrew Davidson and Ian McKenzie. Picture: RCH

Neurosurgeon Wirginia Maixner with a cast of the twins' skulls during a media briefing before the surgery at the Royal Children's Hospital. Picture: David Caird

Trishna gives a big smile. Picture: Lloyd Ellis

Andrew Greensmith, plastic and maxillofacial surgeon, holds a head cast of the twins, showing the skin and skull separation to be performed. Picture: David Caird

Plastic surgeon Tony Holmes talks to the media before returning to the theatre on the day of the operation. Picture: David Caird