True or false? Higher taxes lead to an increase in government revenue

With UK debt mounting, it must be very tempting for the government to increase taxes to provide more revenue. These two articles however show that if taxes become too high, companies and individuals may jump ship and move abroad. Diageo and Unilever have both stated that the 50% income tax and the rise in VAT have made the UK a less attractive place to be based. Can your students think of any better ways of increasing taxes without causing a ‘brain drain’?