Scientists are also developing alternative bloodlike substances which could be injected into the body as a "stopgap" until an actual blood transfusion could be performed.
About two and a half million units of blood are given to patients in Britain every year, costing about £130 each, and modern doctors have minimised the risk of patients receiving infections such as Hepatitis A and C during transmission.
While it would be an imperfect substitute for real blood and therefore not be used in all operations, artificial blood could revolutionise treatment in ambulances, war zones, disaster areas, experts said.
It could also be used in certain hospital situations, for example in elective surgery, and save hundreds of thousands of lives in parts of the world where blood banks are not available.
A team at Edinburgh University has developed a method of taking adult stem cells from bone marrow and growing them in the laboratory to produce cells which look and act almost identically to red blood cells.
Prof Marc Turner said: "I think it will probably be two or three years before we get to clinical trials and I would think it will be a decade or so before one sees these kinds of artificial red cells or cultured red cells in routine general practice."
A more radical solution, which Essex University researchers say could be perfected within five to 10 years, is to develop a completely artificial alternative to blood which performs the same key functions and would be safe to use in patients of every blood type.
This could involve packing haemoglobin – which carries oxygen around the body – into a synthetic cell-like structure, or using a chemical to hold the haemoglobin together so that it can be injected without the need for red blood cells.
Beyond this period perfected artificial blood that would be superior to natural blood could be possible. Stem cell blood that was rejuvenated could provide a stronger immune system and if you could safely keep replenished rejuvenated blood it could provide health benefits. Regularly filtered or replaced blood could also detect and remove any cancerous cells and other diseases and contaminants.
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