Governments have been trying to get businesses to move out of London and the south east for at least 60 years. In the 1960s I can remember Harold Wilson and Tony Benn giving big companies, especially car manufacturers huge subsidies to build plants in the north west and Scotland, but as soon as the market gets tight, the first thing the companies did was shut down their Scottish and north western plants. It had cost them so little to build because of the subsidies, so it cost them little to discard them. Actually, I went to university in Newcastle, when it was still part of Durham University and I can remember Lord Hailsham coming up to Tyneside in the early 60s to try and invigorate the economy and encourage industrialists and business men to move north He was not successful.
I thought if we saw house prices in the south east and London rocket, relatively to the rest of the country, difficulties getting staff when housing was expensive would force companies to move out, but it hasn't. All that has happened is that the businesses have employed migrants, who can be paid little, and who are prepared to live in slum conditions.
I would love to see businesses moving out of the south east, I live there and it getting more and more built up and unpleasant. But nothing any government has done over 60 years has got business men and industry to move north and I doubt it ever will.
The only way for the northern regions to get going again is to do what they did in the Industrial Revolution in the 18th century, build your own businesses, pull yourself up by your own boot straps. Make yourselves a thriving economy again, make the north a land of opportunity and then the balance will shift.