Thanks go to Ed at my workplace for this bit of news, which I'm going to honestly steal:

" A 32-year-old father from Kinnesswood has had enough of speeding drivers who, he says, are endangering his and his neighbours' children. Matthew Henson has taken the unusual step of building his own speed gun and lying in wait to record the offenders' speeds. The vigilante speed warden is compiling the information for a local campaign to get the council to notice the problem since, he says, the drivers always slow down when they see police with speed guns. Mr. Henson built his gun from a ZX Spectrum and the infrared technology from a TV remote control. "

See, it took a while to get to the good bit, but it was worth it. Yeah, a Speedcam made from a ZX Spectrum.
The news was from some car insurance mailing list he managed to get himself onto. Not seen it elsewhere. Wonder if we can get the specs for it?