Researchers at the University of Bristol have found a means of creating a battery capable of generating clean electricity for five millennia, or as long as human civilization has existed.

Scientists found that by heating graphite blocks – used to house uranium rods in nuclear reactors – much of the radioactive carbon is given off as a gas.

This can then be gathered and turned into radioactive diamonds using a high-temperature chemical reaction, in which carbon atoms are left on the surface in small, dark-colored diamond crystals.