Originally Posted by Defs

There is really nothing to speed up, as the process is quite straight forward allready. After landing you'll arrive on ground floor (departures floor) in non-schengen side, as UK is considered "secure". Then you just have to walk towards connecting flights and smaller number gates and go trough passport control on the way. You cannot use automated lanes, but the queue shouldn't be too long even in the staffed lanes. After passport control you can just go directly to gate, there is no any extra hassle.

Basicly, the only barriers are passport control and about 0,5–1,0 kilometers walking, depending which gates you'll gate.