The BBC's David Shukman explains synthetic biology

The emerging field of synthetic biology has been declared a top research priority by the government.

This new science involves designing and creating forms of life that have never existed in nature. The researchers involved believe this extraordinary technology has huge potential for producing new fuels, materials and medicines.

But environmental campaigners warn of the risks of releasing synthetically-engineered organisms.

Our Science Editor David Shukman explains the basic principles of the research.