I had a less-than-pleasant LHR transit experience this morning. It started poorly with a late AA ORD-LHR (AA's issue), then a packed bus-loading area at T3 for T1 (busses seem to run once every 15 minutes, and they need about three times as many busses as they have), then absolutely sluggish FCC security lines. The line I walked past for T3 security was very, very lengthy.

I was peeved that the FastTrak lane at FCC does not recognize BA's Oneworld partners-- so as a Oneworld Emerald I wasn't able to use the line (yet they'll let me use the First Lounge? Doesn't make sense to me).

I ended up going through Immigration into the UK, walked through baggage claim, up to departures, to Zone R, and through security there.

A true positive: no wait for a shower once I got to the lounge.