Thanks, Nick, that was a thundering good read. It seems the beasties I refer to are Truvelo cameras, not SPECS, and they do not measure speed between cameras after all.

Jacqui, have a look at the 'accident blackspots' link on that site, for Lincolnshire. It claims there that the cameras to which we both refer are not powered as 'the Police are waiting for electricity to be supplied'!

It solved another mystery, and proves I'm not the reformed traffic bore I describe above. I was on the way back from a gig in Leeds about a month back, at 1.30am, in the roadworks on the eastbound M180, when I set off a double flash in the GATSO camera that I was driving towards. I must've topped 60mph in a 50 zone, and I was almost asleep behind the wheel. I spent the first fortnight waiting for the buff envelope to drop onto the mat, but am I right in believing Nick's site's assertion that they cannot convict on the basis of driving towards GATSO cameras in excess of the speed limit?