It's oil ok

If I understood Alistair Darling on Good Morning Scotland this morning, he was telling a, to be fair, incredulous BBC reporter that having unimaginably vast oil wealth would be a problem for an independendent Scotland because the price goes up and down. In fact, the ratings agencies made it clear some time ago that the UK would have been downgraded long ago, due to its tanking economy and enormous debt, were it not for the fact that it had sufficient assets (that is, oil) to compensate.