Tax avoidance means significant loses to the Government. The wealthiest people are able to pay a significantly smaller proportion of their income in tax than people on low wages within the PAYE system; this cannot be right.
People who choose to live outside of the UK in order to avoid paying tax (income, inheritance capitol gains etc) should lose the right to a British passport and also their right to vote in elections.
Entitlement to a British passport should require a person to pay their full dues to the state. Anyone who chooses to avoid any of the taxes that may be levied has by default shown that they have no social responsibility to this country and therefore the state should require those persons to relinquish their passport. In the same manner, if such persons wish to avoid paying tax then they lose the right to vote.
Companies who promote tax avoidance should be fined double the amount that they have saved each and every tax avoider.