There is a very interesting article that can be found here:
http://www.spectator.co.uk/coffeehouse/6662858/osbornes-tax-headache.thtml
It points out that to raise the starting rate for income tax to £10,000 would cost the Treasury £5bn.
While the 50% tax rate is estimated to cost the Treasury £5bn.
So this suggests that the government could drop the 50p rate AND by doing so can fund an increase in the nil rate band to £10,000 helping the lower paid.
Seems a no-brainer to me, a complete win-win situation, except that 'he with no brains only Balls' will conveniently ignore estimates of what the 50p rate will lose the Treasury and attack the government for helping the higher paid......