Ms Hall said the charity's ultimate aim was to diminish demand for battery eggs and promote welfare-friendly systems.

BBC: NEWS | UK | England | Battery hens saved for retirement

SpareOne, designed to be an ultimate safety and communication device, provides up to 15 years of battery life when stored unused (off, with plastic tab inserted) or 10 hours of talk time when in use.

ENGADGET: SpareOnePlus adds location tracking, audio alerts, keeps the 15-year life on a single AA battery eyes-on

The ultimate goal of the research efforts is to develop a quantum fluid in this manner operable with a battery at room temperature.

FORBES: Watching Quantum Physics With The Naked Eye