Mr Bean and Hadrian´s wall

The last couple of days have been so hard on her Theresa May had to brace herself holding on to – in her own words – ´a glass of whisky and beans on toast´ – a fine sample of the unsurpassed English cuisine. Both were provided, by the way, by her own dear spouse of 38 years – ´which is a long time´, she added, not sounding as complimentary as she presumably intended.

I still do not seem to be able to quite get my head around all this ado about ´hard border´, ´soft border´, and ´backstop´.
I mean, if I am not mistaken Northern Ireland and Scotland voted Remain, didn´t they. So, why not build (or rather resurrect) a hard border between Scotland and England – problem solved.
There must be some bits and pieces left from the time that England was still great, and its Roman rulers tried to protect themselves from barbarian attacks.