The Office for Budget Responsibility — George Osborne’s excuse for cuts — has presented its first report in advance of net week’s budget.

I’m not through it all yet, but it’s a fascinating catalogue of errors and wild optimism. Take this, for example:

Our central forecast is for export growth to pick up progressively over the course of 2010, before rising relatively rapidly. We expect UK export market share to increase in the near term, as
the boost to competitiveness from the lower pound stimulates a positive response from UK exporters. UK export market share remains broadly stable thereafter, in contrast to its pre-crisis downward trend.

Our biggest market is Europe. They’re in deep recession. Who could possibly think there’ll be a relatively rapid rise in export growth in that case?

But don’t worry — there’s worse to come.