Central bankers will be in the line of fire at their annual symposium in Jackson Hole this week — and they should be ready to engage with their critics. Last year, US Federal Reserve chair Jay Powell used his keynote speech to suggest price pressures would be “transitory”. Annual inflation in the US was then just above 5 per cent. Last month it reached 8.5 per cent. Elsewhere, Eurozone inflation hit 8.9 per cent, and Citigroup…