Set fire to them?
Ah, but what about the ones under trees, outside petrol stations, etc?
Also, I reckon torching them habitually will get you nicked sooner or later, draws way too much attention to yourself ....
Paint on lens etc - too cheap and easy to clean off. We need to damage it beyond economical repair. I'm told they cost £20K each, which means that, assuming the local force keeps around 60% of the revenue, it's only got to catch about 550 speeders and issue £60 tickets to pay for itself. If the ratio of speeders caught to cameras destroyed falls below 550/1 the economic viability of cameras as revenue generators is called into question.
Obviously a case can be made for some camera positions at genuine accident blackspots where excessive speed is known to be one of the primary causes, and i can accept them outside schools, but they should be on a timer and only active at times when kids are likely to be there, not at 2 in the morning.
Now, what about SPECS? Usually mounted on gantries over motorways, so initially I thought they'd be pretty difficult to target, but on closer inspection the gantries have nice wide walkways and hand rails on them, and they even thoughtfully provide ladders at each end. And before someone points out they can't do bikes (yet) some of us also have to use cars for work, I do 60,000 miles a year in one and I'm bound to be caught by one sooner or later.
If having cameras is releasing all those coppers to catch criminals, who's manning the camera vans? And I still see no end of police cars parked on bridges and in laybyes with a laser aimed down the road ...