At General Motors, everybody has their very own nuclear button. The unions could exercise their right to strike, blowing up assumptions for cash evaporation. Unsecured bondholders, envious of terms on offer to the United Auto Workers, could refuse to accept lower claims by the government’s March 31 deadline to agree a reorganisation. The Federal Pension Benefit Guarantee Organisation can impose itself if there is a risk to funding pension obligations. GM arguing for government support, put the requirement for taxpayer cash in the event of full scale bankruptcy at more than $100bn.

Chapter 11 remains the one stick to beat back itchy fingers. Assumptions behind GM’s figures also deserve inspection. GM paints the threat to sales during bankruptcy and long term brand reputation damage as severe, assuming a permanent 10 per cent fall in volumes. Given recent sales declines and the high-profile struggle, this effect is surely felt already. A government guarantee of warranties – a $9bn liability on GM’s balance sheet – would also mitigate consumer concerns.