None whatsover.
There is no fast-track security (and although not as bad as slow-track LHR on a bad day, is can still be 10-15 minutes so you'll be pining for Zone R).
If you did have to queue at a desk, for example to check luggage or because the machine isn't working, the line at the BA club desk seems to be of the same length as that at the other bag-drop desk.
And there is no lounge, so you'll have to wait in the (possibly standing-room only) departure den with everyone else when your flight is delayed by an hour.
All horrible.