How London's Air Ambulance will carry blood
London's Air Ambulance is starting to carry blood supplies, the first such service in the UK to do so.
The innovation has been made possible due to a new refrigeration unit used by the British and American military.
It will allow blood transfusions to be administered on the scene of accidents, rather than later in hospitals.
London's Air Ambulance believe hundreds of lives could be saved, and regional services are looking to follow suit.
Dr Anne Weaver, lead clinician for London's Air Ambulance, showed BBC News the "Golden Hour" box which will make the service possible.