A motorist removed the licence plate from his car in a desperate bid to avoid detection by average speed cameras on the A9.
An astonished witness contacted police when he saw the man speed off after detaching the front plate from his powerful car.
The incident happened in a lay-by just before the Keir roundabout near Dunblane as thick early morning fog shrouded the area shortly before 9am.
The average speed cameras, installed to cut the death toll on the A9, begin on the stretch of dual carriageway north of the roundabout and are in place the length of the road to Inverness.
Police said they had not heard of any such incidents since the cameras were installed in October but confirmed they are investigating this one.
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