Remember that dispute about the staffing of Heathrow Terminal 5? Remember how the threat of industrial action by RMT and TSSA forced management to stick some CSAs there as well as a Supervisor? You may even remember Tubeworker saying that management's promise of "temporary" staffing was not really good enough.
Guess what? Management now reckon that as soon as the barrier on the Eastbound platform is in place, the CSAs won't be needed any more. So who is going to do the various essential jobs that the CSAs do now? Detrainment for instance? Easy - the driver can do it!
On top of this, management are dropping hints that the Supervisor at T5 may not be around for too much longer either.
Which all goes to show that if yousettle for a weak offer, you need to draw your weapons again pretty soon.