Because it was a contractual obligation. Agreed by Labour and the Tories, even if the signature came from a Labour biro. Like the agreement that we would pour several times our national expenditure into a bank bailout scheme that would do little more than prolongue the crisis and guarantee the bust would be huge. We don’t talk about the banks still being responsible for the creation of our money supply. I would have thought, at some point since 2008 we would have had a conversation about whether that was wise. But no. Apparently we are still working on the bonus thing. Do you remember Hester telling us we needed to learn there is no such thing as a free lunch?
PS: Added later. I have seen conflicting reports about whether or not it was a contractual obligation.