Well, in the end, the minister speaks for his or her department; they're one and the same from our point of view. When a department asks something, we don't look at it as the bureaucratic level; we look at it.... They would more often than not inform their minister, “We're not going to go ahead, and we would like your support to change course”, and so forth. So it's not, in that sense, political interference; it's simply the political head of the department taking responsibility for a request.
If you're saying we should refuse such requests if they don't make economic sense, you have a point. What we are discussing now is to what extent.... If you had Public Works saying, “I don't really care what you want, we're moving you to a greenfield site outside”, that would not really be an acceptable way to operate, because departments do have legitimate needs to be in certain places and they have to be accountable for those decisions.
We take a lot of care to try to satisfy a department's needs. I think what you will have found over the last couple of years is that we've become much more rigid about requiring real justifications. So it has improved in that regard, but I think there will always be a need to take into account a department's wishes.