Taxes will go up regardless of of how many bank accounts David Cameron raids, capital flight will begin once the government decides it can take everything people own and Bitcoin, Gold, Silver will all go through the roof as well as other commodities.
You are forgetting that if the government can steal our cash stored in the savings accounts, then nothing prevents them from stealing our gold and bullion also, which is stored in the bank lockers. The only thing which they can't steal is... off course Bitcoins.
And that is the main reason why we shouldn't let governments legiferate bitcoin.