4.1 The deals broadly satisfy the Department's main objectives by bringing in the private sector expertise to manage the upgrade projects, and to maintain the infrastructure on a whole life basis supported by stable funding. Assurance on value for money is limited because of extended negotiations and pricing uncertainty, but there are mechanisms in place (i) linking payment to services for passengers and (ii) to try to ensure the public sector is paying the costs justified by economic and efficient Infracos, for example by appeal to the Arbiter (who may also be called on by the Infracos to protect their agreed rate of return). And there are measures in place to safeguard the public interest.
4.2 The PPP negotiations led to changes to the proposed risk sharing. Deal complexity - in the sense of estimating the additional volume of work needed - contributed to an affordability crunch. Both this, and the political controversy contributed to the easing of some contract conditions and - the Department believes - to the prolonged delays in closing the deals, although Transport for London disagrees. Work to improve the Tube has started two years later than planned and some investment, valued at some £80 million per year, was deferred to later periods. Affordability driven changes spread the period for achieving the desired "steady state" for the improved Tube network over 22 rather than 15 years.