A bug within iOS 5 that causes the iPhone 4S to repeatedly check its location could be behind the problem of rapidly draining batteries reported by some owners of the device.

iDownloadblog reports that it has managed to extend the battery life of the iPhone 4S, as well as the iPhone 4 and iPhone 3GS, by altering a setting in the Location Services menu.

By switching this setting, it is possible to temporarily fix an apparent bug that causes the iPhone 4S to continually check its location - using the position of nearby Wi-Fi networks, mobile masts and using GPS signals as well - and putting an unnecessary strain on the battery.

"It appears that iOS 5′s GM release introduced a bug that causes the Setting Time Zone function to keep the location tracking circuitry running constantly, draining battery power considerably," writes Oliver Haslam on iDownloadblog.

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"Switching it off may mean that your iPhone will no longer set its own time zone when you travel, but that's a small price to pay for having your iPhone last more than 12 hours on a full charge. We have tested this method on 4 different iPhone 4s handsets, including an iPhone 4 and an iPhone 3GS. All have reported drastically improved battery life after switching 'Setting Time Zone' off."

Go to Settings, Location Services, System Services and scroll to the bottom of the screen. Switch the toggle switch for the 'Status Bar Icon' to on and if a purple arrow icon shows up in the status bar at the top of the screen, locate the toggle switch for 'Setting Time Zone' and switch it to off. The purple arrow icon should disappear and your fast-draining battery problems should be over, iDownloadblog reckons.

Some commenters on the iDownloadblog article suggest that the fix works on not only the iPhone 4S, but other iOS devices too. "Nice one, thanks for that, after switching it off my battery life is now as it should be!" one wrote.

"You are a genius! I was wondering why my fairly new iPad 2 was running low on juice much quicker than before the ios5 update. Have got another 2 hours usage time from this!" wrote another.

However, it didn't work for everyone, seemingly, with other commenters saying that the difference was minimal or that they couldn't switch that particular setting off.