Lets say the UK government did this.
1) Lowest business taxes in Europe.
2) Least amount of red tape for businesses in Europe.
3) High Priority Visas for tech people and other sectors like bio, engineering, etc.
4) Investment for setting up businesses.
Pretty much, things that a conservative government which is pro business does.
In one fell swoop they can keep the current businesses here and make the UK attractive for foreign investment and also, with a strong economy. Once again make it a safe bet and keep that AAA rating.
I really wouldn't bet on the UK imploding. Those who say it will, don't know what they are talking about