It appears that the Tories have actually emerged from their decade of irrelevance and stand to gain should this crisis be mishandled. Despite the lack of any real causal relationship, Tory leadership can always blame lackluster economic performance on the taxing of the UK's most productive citizens.

Practically speaking, increasing income taxes during a downturn is always a risky idea. It assumes that this population wont waste resources on trying to avoid the higher rates (maxing out tax-sheltered accounts, loopholes, etc.), especially when they have taking a huge hit on securities losses. Further, the wealthy often have huge discretionary income accounts--they are the best target for spurring consumption; I highly doubt the rich will spend more if their income is taxed more (especially if the increase offsets the decrease in VAT).