There are a number of different types of speed camera.
Gatso are (were?) the most common, and they tend to photograph from behind, but the Truvelo that you find around Portsmouth and in Warwickshire are definitely forward facing ones.
A significant percentage of the Uk's fixed cameras have now been converted to digital. and for these there is no flash, and no need to keep refreeshing the film. First you will know, I'm told, is when the letter arrives advising of your opportunity to make an unsolicited donation to a local "charity".