I once studied heart massage during a first aid course. “Killed her again!” sighed the instructor, as I pounded doggedly away at a practice dummy. It was all so much harder than it had looked on Casualty. Press too gently, and the heart stays inert. Bash too hard, and you maim the patient.

Alistair Darling faces the same dilemma as he works on the pre-Budget report due on Monday. Wielding tax and spend like defibrillator pads, his aim will be to reanimate the flatlining economy with a fiscal stimulus package. This must balance the need for boldness against the risk of lumbering the UK with an incapacitating legacy of higher taxes.