Chancellor of the Exchequer, George Osborne, called on the MPC to follow its American counterpart (the Federal Reserve Board) in committing itself to keeping interest rates low for a prolonged period of time via appropriate forward guidance, which it did on 7 August. These measures eventually proved insufficient to avoid deflation. Having taken over in August 2013, Governor Mark Carney wrote his first open letter in February 2015 to explain why inflation had fallen below 1% for the first time in the MPC's history. This was followed by deflation of 0.1% in April 2015, the first month of negative CPI growth since the 1960s, and triggering a second letter. As of February 2015, Carney has written five such letters. Following the UK's vote to leave the European Union in June 2016, the MPC cut the base rate from 0.5% to 0.25%, the first change since March 2009. At the same time, it announced a further round of quantitative easing, valued at £60 billion, bringing the total to £435 billion. In December 2014, the Bank adopted the recommendations of a report prepared by Kevin Warsh aimed at improving the transparency of the committee's decision making processes. Composition Following a reshuffle in April 2014, the committee currently comprises: The Governor of the Bank The three Deputy Governors for Monetary Policy, Financial Stability and Markets and Banking The Bank's Chief Economist Four external members, appointed by the Chancellor of the Exchequer for a renewable three-year term Each member has one vote of equal weight, for which they can be held publicly accountable. The Governor chairs the meeting and is the last to cast a vote, acting as a casting vote in event of a tie. Representatives from the Treasury may attend the meeting, but only as non-voting observers. Meetings The MPC meets eight times a year, including four joint meetings with the Financial Policy Committee. After a half-day "pre-MPC meeting", usually the Wednesday before, meetings are held over three days, typically a Thursday, Monday and Wednesday. Prior to the implementation of the reforms recommended by Kevin Warsh, meetings were generally held monthly on the Wednesday and Thursday following the first Monday of the month, although this was sometimes deviated from. In 2010, for example, the meeting was postponed from the 5/6 to the 7/10 May in order to avoid conflicting with the general election schedule for the 6th. The May 2015 meeting was