Here's a useful bulb for essential night-lighting: an energy-efficient bulb that automatically comes on when it gets dark. Great for when you're away from home but don't want to advertise the fact. Tidier and less hassle than timer plugs. And they have a 10,000 hour average lifespan.
Megaman Sensor 75W equivalent | £14
Fitting: Standard bayonet (BC)
Power: 15W
Light style: Warm white
Typical savings: £100 & 390kg CO2