It was actually Vince Cable, when he was Secretary of State for Business who talked about London being a black hole and how unhealthy that was for the UK as a whole.
There are many, many studies which talk about the growing inequality in the UK, with the South East/London overheating. Ironically, its growth as a financial centre in the 80s was funded in part by the North Sea oil (and gas) dividend which allowed Thatcher to reduce corporate taxation and provide incentives for financial companies to expand there.
Successive governments have failed to address these inequalities - and indeed have exacerbated them by dismantling or disempowering the regional development agencies. Ironically the EU with the ERDF which tried harder than our own government to help the poorer regions.
Other European countries have improved growth through investing in infrastructure and trying to address these disparities. It is also basic economics - which I can remember covering in my economics degree.
Here are a few articles to provide background (not expecting Francine to read them as they might answer her question don't fit with her premise, but others might be interested). One of them mentions HS2, which is yet another example about how spending in the South East counts as "national infrastructure" (and as such, outwith the Barnett calculation, despite the fact that it comes nowhere near Scotland
). Yet the £billions that the Government has budgeted includes the brand new infrastructure in London and the extra cost of tunnelling beneath wealthy Tory voters the Chilterns but not the cost of the infrastructure in Manchester which is expected not only to find its own funding but also give up acres of prime city centre real estate for the train line (it's "too expensive to tunnel"
)
The Channel Tunnel was a similar example of "national infrastructure". Scotland was promised direct trains - even had a waiting lounge built at Central Station - as part of the financial package, but that was all quietly shelved.
https://fraserofallander.org/scottish-economy/uk-regional-performance-an-increasingly-unbalanced-picture/
https://www.ft.com/content/b91d7d4c-2cb9-11e1-8cca-00144feabdc0
http://blogs.lse.ac.uk/politicsandpolicy/britains-spatially-unbalanced-economy/