Total nonsense. 2 examples. Library provision in lowland Scotland, all built by empire returnees.
Cotton printing industry in Lancashire built on cheap imported cotton.
Your second point; the cotton was cheap because it was grown by slaves. The export market was greatly expedited by the destruction of local industries in the stolen countries. In particular, weaving in Bengal.
Exactly.
Beardy, not so sure about the cotton industry in Lancashire/Derbyshire. I understood it was local workers some of whom may well have been pushed off their land but still local. Happy to be corrected if you have a reference. I grew up in Lancashire/ Derbyshire and my father ran several cotton printing mills.
The main point though is that all of this is clearly available information.
chrisbainbridge is correct about displaced rural people becoming urban factory fodder, but that was mostly in the18th/19th centuries. The Enclosures were one of the causes of displacement.
Beardy's point really applies to the posr WW2 period.