It is why central bankers in euroland and the UK talk of ending stimulus measures but know that if they do, the recovery ends.

But the risks are not uniform, and neither should central banks be in their response.

But he defended the longstanding practice of not disclosing which banks borrow from the central bank' s discount window.

The sellers of these assets can then use the extra funds the Bank gives them, to spend on other investments, or lend to households or businesses.

Banks could rediscount the bills with the ECB but they would not do so as long as they earned more on the bills than on the cash.