Surplus does not equal cash.
When interest rates start climbing up again, every spare penny of CASH will be needed. Unfortunately this type of thinking caused the current problem. 'The current account was in balance over the business cycle' - now who said that?
Economics 101. If you 'borrow' £200K at 3% interest, and spend nothing on maintenance / management, you need £120 rent per week JUST TO MEET INTEREST PAYMENTS.
Simple - divert ALL national resources to the Scotland, Wales, the Midlands, the South West and the North. Leave London and the South East to the private sector and cut HB. Businesses will naturally flow.
The British Economy is badly skewed towards London and the South East. A proper Regional Strategy will help.
Sorry if you live / exist in that part of the country - but it's about time you had to put up with what the rest of the UK has NOW. London Weighting has distorted for far too long. The sooner the South East dominated structure starts to adapt the better.