Not entirely accurate - components of that programme (eg PACS and the Spine) are successes. Not to say that on their own they're worth £12bn, but it's not true to say that the £12bn was completely wasted.
Probably no-one, there will be a lot of "lessons learned" though.
For context, the BBC got £3.7 billion from the licence fee in the 2011-2012 financial year. £100M over a few years is certainly poor, but it's not disastrous.
No-one - it's the civil service. (The BBC pretend they aren't, but they are, just as much as the NHS)