Specialist maxillofacial surgeons Tim Martin and Sat Parmar prepare for a marathon operation on 53-year-old Teresa. Four weeks ago, Teresa was diagnosed with a fast-growing cancerous tumour in her face and she will die within weeks unless it is removed.

The surgeons take on unpredictable, high risk operations. They need to stop a patient's heart, chill his body and drain out all his blood before they can operate to save his life.

The extraordinary stories of clinical trials being carried out at the surgical unit at the Queen Elizabeth Hospital Birmingham.