Just before I retired we had a new Regional Prime Contract. The aim was to maintain 1st rate buildings, to improve 2nd rate to 1st rate and stop 3rd rate deteriorating - or something similar. The contract was fixed price over 5 years. We thought Christmas had arrived early.
For the first year things that had previously been degrading were repaired, painted, replaced etc. At the end of year contract review a big part of the contract was chopped to save money. Needless to say the book cost of the saving was not passed on by the contractor who had bid for a 5-year fixed price.
I don't know what happened in years 3-5 or indeed for the next PPP round.