For those who have been to see the current number one film in the box office charts, most report a feeling of deflation when leaving the cinema after watching Tinker, Tailor, Soldier, Spy. It isn't that the film itself is a letdown, more that it envelopes you so successfully, in a mushroom coloured world of hopelessness, that you cannot but be slightly melancholy when exiting your nearest multiplex.
The film - avoiding spoiling the plot carefully here - demonstrates so effectively the forlorn hope of a better world for those in the spying game, that you are left with an emptiness in your stomach. This feeling is one I recognise from the dark days of Conservative opposition.
More than one Conservative conference ended with a feeling of utter hopelessness - that whatever we did it wasn't going to be alright. Frankly, we were fighting a losing battle. A four hour train journey from Blackpool felt very similar to the hopelessness so successfully communicated in the current adaption of the Le Carre novel.
This is what Labour needs to avoid this week. Nothing else. When their activists start to head away from Liverpool, if they have a melancholy feeling, or an emptiness in the pit of the stomach they will recognise they are fighting a losing battle and should act to change things fast. If they don't, then next year, and I speak from experience here, will be even worse.