Well, sadly no. Because the hyped-up PR gibbons have forgotten one very important fact about next Thursday - the longest day of the year. It won't actually be dark at 9pm. Brilliant.
HM The Queen: I say Philip, it's 9 o'clock and Buckingham Palace is taking part in the Lights Out London event thing. Be a good chap and turn off all the unnecessary lights in one's royal residence will you? HRH Prince Philip: But it's not actually dark, so I haven't turned any of the lights on yet. HM The Queen: Oh bugger.
If you head down to the middle of Canary Wharf at 9pm to experience the magic moment when all the lights go out and the stars suddenly become visible, you're going to be sorely disappointed. Sunset in Londonon June 21st isn't until 9:20pm, and even then it won't get dark immediately. Halfway through the hour-long event it'll still be bright enough outdoors not to need streetlights. Only as 10pm approaches will the sky darken appreciably, at which point the event will end and everyone will switch their lights back on again. Genius.
Still, it could have been worse. Capital Radio were originally planning to hold the event between 8pm and 9pm - far more media-friendly but astronomically even more useless. If they wanted to make a proper impact they should have waited until 10pm for the grand switch off, or chosen a date in the spring or autumn with an earlier sunset instead. But no, they're blundering on with their mistimed event, diluting any appreciable impact that this otherwise creditable campaign might have had.
Of course, even if it's not dark at 9pm next Thursday you can still make a difference by switching off all unnecessary appliances (including those on standby). This may not produce a grand visual gesture across the not-quite-twilight skies of the capital, but the National Grid will certainly notice if enough people take part. Switch Off London, they should have called it, even if that's not as alliterative as the original name. Because the daylight kick-off to Lights Out London is doomed not to be noticed.
As for me, I intend to be hundreds of miles away from the capital at the time, in a tiny fishing village where the sun doesn't set until rather later in the evening. It seems that I'll be participating in Lights Out London by default. So do me a favour. If you see anyone turning the lights off in my flat between 9pm and 10pm next Thursday please ring 999 immediately, because that'll be burglars.