Surely this is an April fool’s day joke – a battery powered by urine? We must be taking the piss. No, it seems it is indeed true; boffins have invented a battery which gets its energy from urine. The innovation came about because of a desire to run cheap, disposable test kits for diseases such as diabetes, in which case the urine has a double role since it is also used to check for the condition. Seemingly, 0.2ml of urine generates about 1.5volts.

Dr Ki Bang Lee, who developed the idea at the Institute of Bioengineering and Nanotechnology in Singapore, said: "We are striving to develop cheap, disposable credit card-sized biochips for disease detection. "Our battery can be easily integrated into such devices, supplying electricity upon contact with biofluids such as urine."