Looking through the detail of the EU's "opening decision" on the Royal Mail pensions state-aid case, one thing stands out strikingly. The fate of the state-owned postal operator hinges on how much the Commission decides its bailout is worth - and at present, it doesn't know if it's £3bn or £10.3bn.

The plan to sell off at least part of the Royal Mail has been in train for close to a year now, and its central plank is the transfer of most of its £28bn pension fund to the UK state, relieving the company of a disproportionate financial burden so that an outside investor can be brought in.