There are not many of us left who remember the last time the UK was blighted by power cuts - the miners' strike of early 1974.
Last month's collapse of the North American power grid and last week's blackout in London, combined with warnings that there could be more cuts this winter, served as a timely reminder of what we could face.
Of course, we've all got high-level disaster recovery plans in place, but have we done the small and simple things that can make a real difference to how we handle a crisis?
Improving your IT department's ability to handle a blackout will only take a few hours and can be paid for out of petty cash. Here is a list of items that may fill some small but critical gaps if the National Grid fails again.
Radios: When the power goes out, you need information. How bad is problem? How widespread? When will the power come back on? Get a few cheap, battery-powered radios or maybe wind-up radios and test them to make sure you can actually receive radio broadcasts inside your office or data centre.
Walkie-talkies: Don't count on your mobile phone for communications. In emergencies, mobile networks get overloaded. In an extended blackout, battery backups for cellular base stations run down. Buy some kids' walkie-talkies to use as intercoms. You don't need expensive models; they just need to work within your department.
Phones: Telephone services usually stay up after the lights go out, but if your phones or switchboards require external power, you can't use them. Get a direct line for IT if you don't have one already and attach a no-frills phone to it.
Computers: A low-power PC on a high-powered uninterruptible power supply, with an internal modem and its own direct phone line will be a lifeline. An old laptop will probably do. On a good UPS, it could run for hours. Add a cheap dial-up account with a national internet service provider, and you'll be able to send and receive e-mail and get information from the web long before your own network is back up again.
ISPs: Have an up-to-date list of ISP access numbers in other cities. Even if our local gateway is down, elsewhere they are probably working fine.
Torches: Buy a few good ones, lots of cheap ones.
Batteries: Batteries for the radios, the walkie-talkies and the torches. Make sure you've got more than enough. Their shelf life is limited, your team will be tempted to "borrow" them, but they are cheap. During a power failure, nothing can take their place.
Contact lists: Make sure they are up to date and on paper. When you've got only one working PC, you don't want to waste power and time searching for vital phone numbers on the screen. Print them out.
Procedures: Make sure they are up to date and on paper. In a crisis, even smart people can forget the obvious. Print out step-by-step instructions and put them in a bright-coloured loose-leaf folder. Then attach a cheap torch to each. Even step-by-step instructions are no good if it's too dark to find them.
Testing: Designate a staff member to check these items each month. That means printing out new copies of contact lists and blackout procedures, updating folders, testing torches and radios, counting spare batteries and replacing equipment and supplies that have gone missing.
Staff time is the most expensive item on this list. But it is the one place you should not scrimp on if you want the benefit of the rest of your preparations the next time the lights go out.