It ought to be the first rule of politics – always stay on top of issues that matter to the people affected by your policies.
Yet time and again we find education ministers who fall short when asked to do simple sums, fisheries ministers who don't know a gurnard from a monkfish and farming ministers who have no idea of the price of a pint of milk.
And now we have an even bigger sin on that theme – with the whole of Government refusing to say how much they pay for the milk to put in MPs' and civil servants' tea, even though ministers are repeatedly calling on retailers and processors to pay farmers a fair price.
At the height of the milk crisis this summer farmers across the West Country blockaded processing plants and supermarket warehouses – as reported in this newspaper – furious that the amount they were being paid for their milk failed, in many cases, to cover the cost of production.
They warned loud and clear that they would go out of business without a better return and quite clearly most consumers backed their cause.
Government, too, showed support and brokered a deal by which the processors and the retailers would give farmers greater security on the prices they received.
It should therefore have followed that, having preached the message of fair prices to processors and supermarkets, they would have ensured their own caterers were paying a fair price for the milk bought and consumed in the Palace of Westminster and Government departments.
Yet the recently appointed farming minister David Heath – Somerset's own MP for Somerton and Frome – has been forced to reply to a parliamentary question on the issue with the lame response that the companies which provided catering services to the Government "declined to say how much they pay their suppliers on commercial sensitivity grounds".
It is, frankly, not good enough. Mr Heath insists that all private companies serving the Government have to meet mandatory Government Buying Standards for food and catering services.
But this is a special issue. If ministers want to stand up for dairy farmers – as they should do – then the best way to do it is by ensuring they pay the proper rate for milk. Without that assurance all their words of support look empty.