David Cameron slams 'spivvy and probably illegal' interest rate rigging ahead of Bob Diamond evidence session Mr Cameron said it was "outrageous" that homeowners may have been forced to pay higher interest rates as a result of efforts to rig the benchmark Libor and Euribor rates. But he refused to back Labour's calls for a judge-led inquiry into the culture of the City saying he believed the matter was better investigated by Parliament. He added that this would be "swift and decisive." However the Labour leader Ed Miliband said Mr Cameron's reluctance to set up an investigation along the lines of the Leveson Inquiry showed he did not understand the scale of public concern over the banking scandal. The clash at Prime Ministers Questions came ahead of Mr Diamond's evidence to the Treasury Select Committee this afternoon. He is expected to be swiftly followed by the Deputy Governor of the Bank of England, Paul Tucker. This afternoon the Bank said Mr Tucker was keen to give evidence "as soon as possible." Both men are expected to quizzed about an email released by Barclays yesterday suggesting the Bank of England may have encouraged banks to doctor their borrowing costs during the financial crisis. The email - an account of a conversation between Mr Diamond and Mr Tucker - appears to show Barclays was under the impression that manipulating rates was being sanctioned at the highest level. It could also implicate senior Treasury officials. "There is a hearing of the Treasury Select Committee when this will be addressed," he said. Ahead of the Committee hearing, Labour's former City minister Lord Myners said he did not think any of his Treasury colleagues, under the leadership of Alistair Darling, discussed the rate with the Bank of England. Conservative MPs highlighted the reference to pressure from Whitehall, suggesting that former Labour ministers had to explain their involvement. But Lord Myners said: "We were not interested in the Libor-setting process, let alone the submissions by individual banks. I don't think it was on our agenda. I don't remember it being discussed at all. Alistair Darling, who was chancellor from 2007 to 2010, said yesterday he did not believe anyone at the Treasury would have urged such improper intervention by the BoE. However, he appeared to stop short of expressing confidence that no one in government would have done so. Firstly, I think it is important that this committee which is examining Bob Diamond tomorrow also gets Paul Tucker in front of it at the earliest possible opportunity. Because this is Bob Diamond's account," Mr Darling said. Shadow chancellor Ed Balls, a close ally of Gordon Brown and a Treasury minister in 2006/07, insisted he knew nothing about the issue. "I have absolutely no idea, that's why I want, as Ed Miliband does, a full open judicial inquiry at arm's-length forensically to ask these questions to see whether anybody knew what was going on," he said.