The Palace of Westminster is in need of a major refurbishment that will cost billions of pounds and this creates a golden opportunity to move the UK government to Sheffield, Leeds, Manchester, Liverpool or another suitable location. The effect of moving the UK government to a Northern city will be to create a true and lasting Northern powerhouse through the building of airport, rail and road infrastructure and the services needed to support them. It will create lasting employment in all sectors and through wealth creation will lead to a more financially balanced United Kingdom. The value of property will increase due to the additional movement or opening of embassies, consulates, think tanks, consultants, auditors, business and government agencies and other support organisations.
London will of course lose some of these organisations but with the Palace of Westminster renovated and converted for uses such as a History of the United Kingdom museum losses should be minimised. In fact London is and will increase as a very popular tourist destination. New York does not suffer because the government is in Washington. From the point of view of unifying the United Kingdom it will have the effect of making ordinary citizens feel for the first time that they matter as much as those who live in the South of the country.
See differences in unemployment rates, types of employment, property prices, facilities, opportunities, individual wealth etc between London and the South East and the rest of the of the United Kingdom.