Robert Peston on Facebook:
“Schrodinger’s border” is a senior Tory’s name for what the government has to create between Northern Ireland and the Republic: a border that both exists and doesn’t exist at the same time.
Or to put it another way, there has to be enough of a border so that after we leave the EU, the rest of the EU isn’t fearful that goods failing to meet their standards leak from the province into the EU single market.
They don’t want US chlorinated chicken polluting EU coq au vin, for example, which might happen if we succeed in doing a trade deal with Trump’s America and there aren’t border checks.
But the border can’t be so real that it stimulates the kind of smuggling and crime which in the past has funded terrorism.
So the border somehow has to exist and not exist.