It’s not as if the government weren’t aware, is it?
https://www.connexionfrance.com/article/French-news/Port-of-Dover-queues-A-one-off-or-a-long-term-problem
/The UK government rejected a £33million proposal by the Port of Dover in 2020 to double the number of French passport control booths from five to 10 in anticipation of lengthier checks linked to Brexit.
Tim Reardon, head of EU Exit at the port, said French controls would get “more intrusive, and therefore slower” after the UK had fully left the EU, the Financial Times reported at the time.
“That means we need more French kiosks in order to maintain the rate of flow,” he said.
But the British government turned down the port’s request, which was made as part of a £200m Port Infrastructure Fund set up to manage the consequences of Brexit. Instead, it gave the port £33,000 for unrelated work.
Mr Bannister, CEO of the Port of Dover, told the BBC in 2020 that the lack of funding would make the transition to Brexit “more challenging”.
“Being denied the funding for this programme…What that does mean is that we could see increased friction and increased hold ups while we get through the opening period of the transition," Mr Bannister said.
The issue is that French border police now have to stamp Britons' passports and carry out more rigorous passport checks that could involve assessing visas, specific entry dates – UK citizens can now only stay in the EU for 90 in 180 days without a visa, etc.
Prior to Brexit, these passport checks were more cursory./
But of course, let’s blame the French.