Even before Lord Kerslake was asked by Labour's shadow chancellor John McDonnell – the two knew each other when both were at the Greater London Council in the 1980s – to conduct a review into the Treasury, the knives were out for the department that for decades has dominated Whitehall. Then came Brexit…

The long tail of the recession with low productivity and stagnant wages, continuing austerity, missed fiscal targets and over-optimistic forecasts, the ‘omnishambles' budget in 2012, and finally its dire warnings about the impact of Brexit which have not come true, have all damaged the reputation of the Treasury.