period, with each contract receiving around £660million each month from the Government, albeit with reductions if targets are not met. Commitments under the PPP Under the terms of the PPP contracts, Metronet agreed to maintain London Underground infrastructure (track, trains, tunnels, signals, and stations) to the standards and performance levels set in the contract. Furthermore, Metronet committed to delivering substantial improvements to the network, by refurbishing, upgrading and renewing track, trains, tunnels, signals, and stations. To encourage high reliability, deductions suffered for poor performance were set at twice the rate of increase in revenue for improved performance. At a cost of £7billion, Metronet promised substantial investment during the first 7.5years of the contract (2003 to 2010): 147 stations (including lifts and escalators) modernised or refurbished by 2012 of track renewed and 166 points/crossings replaced Upgrade and refurbishment of tunnels, bridges, embankments, track drainage and other civil structures Refurbishment of existing rolling stock, as well as making them more reliable 47 new trains with upgraded signalling on the Victoria line by 2012 (delivered as 2009 Stock) 190 new air conditioned trains for the District, Circle, Hammersmith & City and Metropolitan lines by 2015 (delivered as S Stock) 24 new Bakerloo line trains by 2019 (cancelled following the collapse of the PPP) Performance and criticism In June 2004, the National Audit Office criticised the complexity of the PPP deals, noting they offered "the prospect, but not the certainty" of improvements. In August 2004, Metronet was declared at fault by an accident investigators' report into a May 2004 derailment at White City, for failing to implement sufficient safety checks despite being ordered to do so by TfL. In March 2005, the House of Commons Transport Select Committee noted that "Availability is the most important factor for Tube travellers. All the infracos needed to do to meet their availability benchmarks was to perform only a little worse than in the past. On most lines, they did not even manage that." In March 2005, the House of Commons Public Accounts Committee, charged with ensuring value for money in public spending, published a report concluding that it was "impossible to determine" whether the PPP was better value than a publicly run investment programme. In April 2005, the Commissioner of Transport for London, Bob Kiley, pressed for an urgent review of the PPP, describing its performance as "bordering on disaster". TfL also said that new technology promised