Last Saturday I revealed that Danny Alexander will use the Lib Dem conference to articulate his differences with Tory partners over green energy and employmeng legislation.
The event is likely to see many more moments of differentation, and not only from the usual suspects such as Tim Farron or Vince Cable.
While the Tory leadership (if not transport secretary Justine Greening) has swung behind a third runway at Heathrow, the Lib Dems are determined in their opposition to the scheme.
The motion says that Heathrow is “extremely badly located” and repeats that the Lib Dems remain “strongly opposed to the third runway“.
It repeats the coalition rejection of new runways at Heathrow, Stansted or Gatwick. It then goes further and voices opposition to mixed-mode at Heathrow, which the Tories are keen to push as an interim measure for the next three years.
(I revealed on July 1 that the coalition has put any aviation decision into the long grass until 2015 and that the Tories will not mention Heathrow in their manifesto to enable a U-turn in the next Parliament.)
The Lib Dem motion, from backbencher Julian Huppert (who has a behind-scenes DfT role) also rejects a new Thames Estuary airport, contrary to the wishes of many Tory MPs.
Instead it proposes:
* An end to lower landing fees at Heathrow
* Movement of “point-to-point” flights from Heathrow to other airports through a re-negotiation of EU slot allocation rules. (Or even a new Heathrow departure tax to shift flights elsewhere).
* Use of existing capacity at airports including Luton, Birmingham, Manchester and Edinburgh
* The introduction of per-plane duty instead of the current per-passenger duty to incentivise full planes. (This is something the coalition was meant to do but has quietly dropped).
All of this is exactly what the coalition should be examining if it was serious about sticking to its 2010 pledge not to expand Heathrow, Stansted or Gatwick. Given the U-turn of Osborne and Cameron on Heathrow, however, it seems possible that the proposals will be entirely ignored by the Tories.