Generally there are two types, a white van with the camera equipment poking out of the rear (for layby based vans) or out of the sliding side panel (for overbridge based vans) They are not required by law to carry a 'speed camera warning' logo, (although government guidelines state they should) although by the time motorist has seen it, their speed has been recorded anyway.
Generally, there are two categories: a white van with camera equipment visible from the rear or side panel (for layby and overbridge-based vans). They do not need to display a 'speed camera warning' logo legally (though guidelines suggest it), as motorists will have had their speed recorded by then.