The Bank of England’s Deputy Governor Paul Tucker admitted Monday that he couldn’t be sure that regulators had put an end to private sector manipulation of the key interest rate.“I can’t be confident about anything after learning about this cesspit,” he replied. Cesspit is a very strong word for a banking regulator to use about the behavior of Barclays Bank. This bank is considered one of the jewels in Britain’s financial system crown. This is not to say that the charges that Barclays (and possibly many other banks) have been improperly influencing Libor are unimportant. Libor is supposed to represent the cost at which banks are able to borrow money from other banks.