Originally Posted by 108912

I cannot answer on behalf of that poster but for me
1) I commute to an office that is literally on the doorstep of LHR. I MUCH prefer the train although it is often impractical.
2) there is no domestic air competition
3) One way peak hour trains on Avanti for Standard Class are around GBP180 from Manchester Piccadilly - Euston.

I guess for most that fly BA to MAN, they will be connecting on from other BA/non BA flights at LHR so left with the option of A) sucking up the dreadful BA experience or B) dragging their bags on the tube to Central London to then board a train.