Trewser your post seems somewhat disingenuous at this stage, after years and years of discussion on here and elsewhere.
I apologise if that is not true, but I have spent a lot of time on threads reading and explaining about Brexit and the UK's border with the EU.
The border is in Northern Ireland.
Not in the English Channel.
And your border in NI is unique, as it is overseen and protected by the Good Friday Agreement.
Thanks to the GFA, people in NI can now travel over and back with absolutely no impediment.... as Boris described it, as if they were travelling from Chelsea to Westminster.
Except that, after Brexit, it simply will not be possible to maintain that openness.
Why?
Because, if I am an unscrupulous sort, and I want to smuggle people into Britain, or I want to smuggle chicken/beef out of Britain, then I will exploit that open border.
Unscrupulous Me will fill a van with trafficked people in Greece, or Italy or Lithuania- then thanks to the EU Freedom of movement, I can bring them as far as the Republic of Ireland.
If, as Boris claims, the open border between the UK and the Republic, will stay as open as it is now, then there is nothing to stop Unscrupulous Me from bringing them into Northern Ireland and hence on to Edinburgh or Bristol or London, or Nottingham or Liverpool etc etc.
In reverse, if the UK crashes out, and there are no more EU regulations on the quality of food, then Unscrupulous Me can fill my empty (people trafficking) van with meat. Or even live animals.
Then I can drive from (insert your local British town) to Northern Ireland and into the Republic.
I can then claim that this meat is from the Republic....selling it on to France or Germany or even filling Irish beef orders to the Middle East.
The first time that beef tests as not meeting EU standards- that will be the death knell for those countries buying from Ireland ,or indeed, buying from elsewhere in the EU.
So, the EU cannot allow that.
Clearly (or, it seems so very very very clear to me) that is untenable and will not be allowed to happen in either direction.
Hence there must be Border checks.
Unfortunately, given the history of Northern Ireland, the paramilitaries (who haven't gone away, you know) the person doing the checks, their office, their car, their clerical support, immediately becomes a target for intimidation and threat.
So, this is the dilemma.
One that the UK is paying their politicians to work out.
Except that their politicians seem to be too busy lining their own and their cronies pockets to spend time on coming up with reasonable answers.
There is no simple answer.
There was no simple answer to the War Troubles in Northern Ireland. The GFA involved lots of difficult work over many years, with many difficult brave compromises by individuals from every side.
It is (as I've said before) sinful to attempt to throw the GFA away so lightly.