Its not the Poles, Its our lack of abillity to compete as a country. We operate in a world marketplace.
To be a successful economy one or more of 3 conditions have to exist
1/ You conquer/ run a vast empire and rake in the proceeds and efforts of your dominions. Those days are long gone.
2/ You have vast mineral/ natural resourses wealth (eg Saudi Arabia Norway) and live off the proceeds. We,ve squandered ours.
3/ You make things the rest of the world desires and sell them at a price the world likes eg Germany-with their millions of of migrant Turkish workers- with big ticket stuff even the Chinese can,t get enough of. Or China who mass produce low ticket stuff the world buys up.
100 years ago Britain led the field in Manufacturing. What of world renown do we manufacture now, off the top of my head- Rolls Royce aero engines, JCB earthmoving equipment, Scotch Whiskey, errrm

Oh yes weapons systems. Im struggling now!
To support this rapidly expanding population and get them to work we have to start to become competative again. The square mile will not feed a population of 70,000,000 plus.