http://driving.timesonline.co.uk/tol/life_and_style/driving/article3508185.ece

First the I told you so of average-speed ticketing that would come
eventually if tracking were used on the roads. (they are using the
numberplate cameras instead of transponders, but the theme is the same)

"Unlike Gatso or Truvelo cameras, which typically cover less than 100
yards, average-speed cameras work in pairs to cover several miles. They
use numberplate recognition to record the time it takes a driver to
travel between any two points and work out the average speed."

But it gets even better... to enhance the profit they are lowering the
speed limit to 50mph!

"The Department for Transport (DfT) is developing plans for the rapid
installation of average-speed cameras, starting with the 500 miles of
motorway where it is planning to turn the hard shoulder into a running
lane. The limit will be reduced to 50mph or 60mph, with gantries over
the motorway carrying signs and cameras."

But it gets better yet.... if you just pay them you can go ?70mph?:

"It also entails converting the hard shoulder into a running lane and,
from 2010, turning one lane into a toll lane with a higher speed
limit."

Then there is this idiocy:
"The DfT says that compliance with the limit is essential when the hard
shoulder is not available for breakdowns."

50mph is more than enough to kill if you're going to have broken down
vehicles in the road.