I don't think it's surprising.If one looks at the make up of...

I don't think it's surprising.

If one looks at the make up of FTSE 100 you'll find its very much comprised of:

Huge financial institutions including multi-national banks
Miners
Utilities
Pharmaceutical companies
Supermarkets
Tobacco companies
Brands Coca-Cola, Burberry

Many of these are unrelated, at least directly, to the UK economy.
Others will always be making huge revenue due to the fact that people go shopping for essentials and use power and water.