And the full context: he was referring to accusations that the government were ignoring the advice of economists and trade experts on the subject of Brexit. The accusations were that this was because the advice didn't fit in with the UK government's stance on the matter.

He was using the example - nearly ten years on - of how "experts" didn't predict the 2008 crash. At best, a straw man argument (which experts; were any expert advisors aware and did they endorse the extreme lending that affected the UK, etc.)