According to the government:
"The hard shoulder should only be used for breakdowns and emergencies. It is not a place to stop to check maps, make phone calls (except in an emergency), have a rest, drop off passengers or pick anyone up, except in an emergency."
So, if it is sunny and you have a convertible with its roof down and it starts to slightly "spot" with rain, and you decide you want to put your roof up, is that an emergency?
Is it ‘eck as like. There were several drivers on the M4 this evening doing just that. (I wouldn't have minded if it was a terrential downpour, but it was just spotting with rain!). If you put your roof down you should expect to get the occasional soaking in this country. That doesn’t mean you should endanger lives to do avoid it.