No, I got busted whizzing down the single carriageway on the A1, I lifted my foot off the accelarator when I spotted the camera in the distance, saw it was on the other side of the road and also pointing toward me, so I sank the foot again thinking what you have just asked, and was papped :(
The Association of Chief Police Officers' guidelines suggest that a fixed penalty is not applied (in a 60mph zone, which I assume this is) until 68mph. So, depending how much "just under seventy" you were travelling, you may have got away with it.
The trouble is I'm not sure whether the limit was fifty or not.
It is the road from Helston to Lizard and there were so many different changes of speed limit I was bamboozled.
One would think that in a three-lane situation like that it would be 60 but I can't be sure and I am not going to drive all the way back just to find out.
One interesting point to note is with SPECS cameras - which check your average speed over a section of road you have to stay in one lane for them to work e.g. if you pass the first camera in the slow lane then change to the middle lane before you reach the second camera your speed can't be validated. Read it in the motoring section of the Daily Mirror if anyone wants to contradict me - blame them :-)