I just wanted to post a recent positive experience I had. For the past few years my passport has consistently failed at the e-gates at LHR. Within that time I changed my passport and it still didn't work, but last week after begrudgingly heading straight to the e-gates at T5 on arrival from Munich, to my surprise it accepted my passport. Normally it would reject it immediately, which made me think it wasn't a technique issue, as they normally ask you try again in that case. I guess what I'm saying is don't give up hope if your passport never works, and even if you normally manage to slip straight to the desk, just consider trying the e-gates every now and then.