It is highly undesirable but unfortunately necessary. The problem is that we should not have banks which are "too big to fail". Instead of supporting giant "national champions", governments should have been enforcing higher standards on banks as they approach this "Too big to fail" level, both to reduce the chance of having to bail them out, and to squeeze risky behaviour out of them into smaller, "more agile" banks which can be allowed to fail if they get it wrong.