It contains a legal obligation on the government to spend 0.7% of GNI from 2013 on official development assistance.
In my view laws shouldn't be introduced for the sole reason that they constrict future governments. One generation shouldn't dictate to another like that.
But there's a more important point about the debate over international development, which is overwhelmed by cries for more funding.
In other sectors these voices are at least matched by calls for improved effectiveness in the way funds are spent.