

Where in Berlin are they going to find a spare platform they can install UK immigration control infrastructure around (of the sort they have in Paris/Brussels)? Given the long distance such a journey would cover, the demand would be lower than from a 3-hour Eurostar trip, meaning that taking a station platform and enough space for passport control booths just for a few passengers would be of dubious value.
The fact that these dinguses have more money than most people will ever see in their lives and spurt unimaginable sums of it up the wall in the throes of delusions, commanding thousands of lives and squandering resources that could have built useful things is a repudiation of the just-world meritocratic ideas that rationalise the status quo.