Walking into work today, I pass a large gaggle of policemen busy pulling apart a BMW by the side of the Holloway Road. A couple of vehicles are positioned either side, and one of the dayglo jackets says "DVLA Evasion Unit". Aha! Now, if I'm right about how these people work, there'll be a mobile computerised camera unit a hundred yards down the road… and there, trying to look inconspicuous outside Holloway Road tube, is my baby.
It's some nerd's idea of undercover surveillance -- a white van with blacked-out windows. That by itself wouldn't be too bad, but the nest of weird aerials on the top, the generator puttering away on the pavement and the sheer number of windows gives the game away somewhat. In an attempt to blend in, the forest of black VHF and UHF rubber whips on the roof are joined by an eggbeater TV antenna, the sort you get on caravans. The overall effect is one of a radio ham's mobile love nest, and I give it a good stare before ambling on my way.
This is ANPR -- Automatic Number Plate Recognition -- and works by optical recognition of passing cars. The van is linked to the police national computer and other databases, and if a motor flashes up as suspicious the occupants of the van radio ahead and get their pals down the line to stop the vehicle and make enquiries.
It's also desperately vulnerable to some plonker kicking over the generator, scrawling "BIG BROTHER IS READING YOUR PLATES: TURN LEFT IF YOU'VE SOMETHING TO HIDE" on a sign just down the road, or coming back to the scene of the crime a few minutes later armed with radio scanner and laptop to see what they can make of the digital communications spurting out of the top.
Not that I would, of course.