Of course, the most difficult cameras to avoid are the brand new ones and the mobile ones which regularly change position. To guard against these, TomTom's community reporting function comes into play. This allows you to press a single button to send a message that there is a new camera at the current location. You can swipe left and right to choose between reporting a new fixed or a new mobile camera.
If you are notified of a camera which no longer exists at that location, you can report that, too. The reporting button changes from an addition to a subtraction when a location warning is in progress, so clicking it will have the opposite effect. Your reports are uploaded to TomTom's servers, and the latest data is downloaded.
It's worth noting that although you can obtain safety camera databases for a number of European countries for use with TomTom Speed Cameras, there are some notable exceptions. Switzerland and Liechenstein have outlawed this information for some years now, and in February 2012 France did too, although sat-nav software is allowed to warn of "danger zones" where cameras might be, offering a randomised hypothetical location. In the UK, though, there's no controversy, and services such as Speed Cameras provides are considered an additional safety provision.
Since its release, TomTom's Speed Cameras hasn't garnered the best user reviews on the iTunes store. But we didn't find any omissions in its listing during our testing around London and the Home Counties. The issues mostly revolve around how quickly new mobile camera locations are added to the database. With a system that relies heavily on user reporting like this, you need user participation to make the service a real success, and it's early days for Speed Cameras. There are also free alternatives that have a decent reputation, such as CamerAlert from PocketGPSWorld.com. TomTom Speed Cameras has a great interface, and is well worth the £1.49 trial. But we'd recommend trying the other options too before purchasing the annual subscription.