How?
How have they spent this much money? What on earth are they doing?
I mean, I get how you could spend a few million on getting a good size team of decent developers to build your application for you and more for some solid hardware to run it on or to hire the cloud services that it will need, but sixteen billion???
That is more than the annual cost of all unemployment benefits put together. What is wrong with them?
This is where private sector involvement falls down. If they had simply recruited and employed all the staff needed to design, implement and maintain this, it would have cost far less than they have already spent. The British government spends far too little on hiring good people, too much on horrible, awful, appallingly designed private sector contracts. Great if your ministers want a directorship but a shitty deal for us as taxpayers.