If ships are skipping UK ports to stay on schedule.

Your opportunity to containerise say UK East Europe frozen food trade to avoid Dover either disappears or cost rises hideously.

A container ship can't just pick the emptiest port at short notice. It can cancel but not rebook.

These things cost so much money and require HUGE fixed costs, plant infrastructure, staff, IT, services, trucks and long term planning.

If a regular cancellation becomes semi permanent it can take 2-3 years to persuade a line to rebook.

Structural irreversible loss.

30 years ago there were smaller feeder lines of smaller ships doing odder routes. Most cross channel North Sea will these days be done on spare space on intercontinental routes doing half a dozen European ports and one in UK.

It's not like diverting a jet due to bad weather.

If they can't unload rapidly, quickly as planned in the place they are booked at - it will either just get chucked off at least inconvenient point maybe 800 miles away - say Hamburg - or even - stay onboard and end up back in Singapore - the main interchange - to try again.