The world's top five cell phone makers have launched a common energy rating system for phone chargers, in the hopes of making it easier for consumers to compare and choose the model that consumes the least energy.

The new rating system has been developed and supported by LG, Motorola, Nokia, Samsung Electronics and Sony Ericsson and will ranges from five stars (for the most efficient chargers) down to zero stars for those guilty of consuming the most electricity.

The cell phone industry has become the world's top consumer electronics business by volume and environmentalism complaints have been frequent and persistent.

Chargers actually continue to use electricity when left plugged in, even when the phone is disconnected. Around two-thirds of the electricity used by cell phones is wasted as a result.