All I can say is I've never seen strangers or other drivers shout insults at people for driving worn out cars. I could imagine it happening if the driver of the worn-out car is holding everyone up, but English drivers tend to show their contempt of slow drivers by speedily overtaking them. Leaning out the window and yelling at them sounds like something an American (no offence) in a city like New York is more likely to do. Although I'm not saying it wouldn't happen in England, there are probably London cabbies and van drivers who do that.

What I'm trying to say is people are more likely at driver for the way they are driving, not for how worthless their car is. Although I've seen driver yell at cyclists (it's happened to me before), and I've seen cyclists swear at car drivers.

If a car is so clapped out it can't keep up with the speed limit and is causing an obstruction and leaking smoke and such then it shouldn't be on the road in that state.