Positive Money has just produced this paper entitled "Would a Sovereign Money System be Flexible Enough". The paper deals with full reserve banking: that's a system where private banks cannot "print" or create money - only the central bank is allowed to. Certainly I see no reason why the profits derived from seigniorage (aka money printing) should be captured by private banks.
The paper refers to a mysterious critic of PM’s ideas who claims that a Sovereign money system would result in “a shortage of money, high unemployment and low economic activity..”. But the critic is not actually named. Well after approximately 30 seconds of Googling, I tracked down the offender: it’s Ann Pettifor.
Evidently Ms Pettifor hasn't tumbled the fact that the UK’s finance minister at the height of the crises, Alistair Darling, created £60bn of sovereign money (aka base money) at the click of a computer mouse for the benefit of two failing bank. Plus she is presumably unaware that the British state created vastly more than that amount of base money (also at the click of a computer mouse) to fund QE.
Lack of flexibility - my ar*e. Under a Sovereign money system, government and the central bank would have no more difficulty implementing stimulus (via creating and spending base money) than implementing the right amount of stimulus under the EXISTING system.