The theory behind the CEBR report is that companies have a reason to stockpile – and virtually no cost of doing it while interest rates remain near zero. There is little history to go on because it’s unusual to have an economic event looming that can be quantified in its effects from mild to disastrous. Usually economic events come as a surprise and companies, faced with a collapse in consumer demand and nervous banks that refuse credit, react by running down their stockpiles.

The CEBR chairman and economist, Douglas McWilliams, accepts that his report is based on “anecdotal evidence, surveys and intuition” but still believes GDP will be 0.5% on average above the underlying trend over the three quarters from July 2018 to March 2019.

There is a cost to bringing forward billions of pounds worth of purchases, and that will be a reduction in GDP by the equivalent amount during the rest of 2019.”