In this post-financial crisis world, the Fed has taken a Keynesian edict and turned it on its head: instead of the government stepping in after a crisis to make up for the loss of aggregate demand from the private sector, it has fallen to central banks.
But it may be worth remembering that theaggregate public-sector and private-sector indebtedness of the UK is higher than for any eurozone country, even Greece - and our annual government deficits are significantly greater than those of Spain or Italy.
What it would do is shift economic activity from the less productive government sector to the more productive private sector, thereby stimulating aggregate output and growth.