Bob Diamond had a conversation with Paul Tucker about how much Barclays was claiming it had to pay to borrow money during the financial crisis in 2008.
After Mr Diamond spoke to Mr Tucker, Barclays staff came to believe the Bank of England wanted them to falsify this data — which was used to calculate Libor, the interest rate that banks pay to each other.
http://www.telegraph.co.uk/news/politics/9369042/Bank-of-England-dragged-into-rate-rigging-row.html