(It's like one of those school maths problems with water running into the bath and pouring out again at various rates).
from a forthcoming book
Seen this happen when I worked in haulage at cairnryan and Lochryan ports when management had p issed the staff off and paperwork checks and unit and trailer checks started to be done a little bit more thouroughly. The queues would be 5 or six miles back in no time. And these are small ports compared to Dover