A programme is a set of projects linked by a common goal or objective. Project management is relatively well understood (although not perfect it is more a science than an art). The programme itself needs good governance in order to meet the needs of the business.
Good project management will save you contingency (commonly 30%) if well managed. However, doing the wrong project or doing a project out of sequence can cost much more than any savings made within each project. How may projects have been quietly canned when people realise they are not quite what was required or the scope was not well understood?