Signing up is the first step in showing your support for Lights Out London. By confirming that you, your school or your company is going to participate, you'll help show that London is serious about going green.

Plus, everyone who signs up will automatically be entered into a competition to win one of five Sky+ systems including a year's free subscription to Sky's top entertainment package Sky World, plus two energy saving light bulbs. By using these light bulbs in your home, you'll save the same amount of energy your Sky+ box will use over its lifetime. Please see Terms and Conditions.

It's important that we get as many Londoners as possible to sign up, so tell your friends! The more people who take part, the bigger the message that we will send to the world - so register now!