I don't believe in taxing anyone more than 50% of what they earn (and the current top rate is 52%). It seems intuitively unfair. In addition, it has not been shown to be effective to raise tax beyond a certain level. On the other hand, we have to recognise that tax is political and not merely economic. It would have been tough to not ask the bankers to contribute more after having only kept their jobs thanks to a huge taxpayer injection.
People are mobile, up to a point. Tax the rich too highly and they will leave. The question is where that tipping point lies. Clearly the current rates are close. The thing is that most high earners are also wealthy and tax on wealth is still a lot lower than tax on income (CGT at 28%) so it is not a simple equation. Most people prefer to stay in a familiar country with their family and friends if at all feasible economically. I don't think a lot of people will leave at current rates but young hedgies with no family will almost certainly depart.
Muminbeds,
Anyone who owns their own business and pays 50% tax needs a tax advisor as a matter of urgency! Why not pay themselves a smaller salary and more in dividends, which are taxed at a far lower rate? As well as there being plenty of other allowances for entrepreneurs (EIS, VCT etc etc).
Nepko,
I do not know if you really misunderstand laffer curves that badly or you are just being inflammatory. Clearly, there is an optimum point of taxation for revenue raising. It is certainly not 0%.