I make a few trips a week between Jn 10 and 3 of the M25, and have noticed in the last few months a number of brand new 4 x 4s with 'jam sandwich' type paintjob, but with green and yellow (I think) checquers on the back, flashers on top and 'highways agency' lettering on the back.
What's that all about then?
Have noticed most cars drop down to the 70 mark when overtaking them, and have seen a couple parked up behind cars on the hard shoulder.
Who are these fellas and what do they do?