The first British patient to contract the Ebola virus is now being treated with the highly experimental therapy ZMapp, touted as having saved the lives of two American healthcare professionals.

The drug, a cocktail of three antibodies against Ebola, is being developed by tiny San Diego, USA-based biotech Mapp Biopharmaceutical, which has just nine employees.

Twenty-nine year old nurse William Pooley, who was struck down with Ebola while working as a volunteer nurse in Sierra Leone, was flown to RAF Northolt on Sunday and taken under police escort to the Royal Free Hospital, where he remains in an isolated unit.

He received the first dose of ZMapp - which has not been tested in human trials and supplies of which are extremely thin - on Monday, and according to media reports is his condition is stable. 

Ebola was first encountered in 1976, but no cure has been approved for the illness, which can have a mortality rate of up to 90%. Treatment strategies currently focus on addressing Ebola’s symptoms, such as diarrhoea and vomiting.

Over 2,600 people in parts of Africa - including more than 240 healthcare staff - have now contracted the disease.