It must have seemed like a good idea at the time. Yet since Angela Merkel began appointing non-politicians to her campaign team, the German opposition leader has learnt the hard way what many managers have discovered to their cost: excessive reliance on outside consultants is not good for business.

It began three weeks ago, when the woman who looks set to take up residence in the Chancellory later this month, handed Paul Kirchhof, a former judge and tax expert, the budget portfolio in her shadow cabinet.