Ye canny change the laws of physics

So, the water board folks arrived to fit a new 30mm meter in place of the 15mm one. They dug a big pit around the old meter and were about to fit the new one, when I checked that the connecting pipes were also 30mm.
Workmen - "No, no they're 25mm"
Me - "So what's the point of fitting a 30mm meter to a 25mm pipe then?"
Workmen - "Oh, it won't make any difference. The 30mm meter will give a better flow rate than the 15mm. Far better"
Me - "Maybe so, but not as good as if it was connected to the right size of pipe"
Workmen - "Oh, no, it won't make any difference. The 30mm meter will give you much better flow rate. Beautiful plumage"

OK, they didn't say that last bit. I phoned their supervisor who, for an employee of a water company seemed also to have great difficulty getting his head round the concept that the flow rate of water in a pipe is determined by its narrowest point.

They're fitting the new meter now, but it looks as if the pipe from the stopcock in the street may have to be replaced.