Originally Posted by
stifle
No. Being downgraded is not denial of boarding and does not trigger duty of care.
(I'm sure the board's pedants will be along shortly with a what-if situation involving a blind, deaf, wheelchair-using passenger who only speaks Kannada, has 25p and a £100 Scottish note in cash to last them till landing and hasn't flown since 1999, but the above would be the general answer
)
In practice what would happen, if (on a far more reasonably hypothesis) a Pax is downgraded and says
"No I do not want to be downgraded, I want to travel in the class that I paid for"? Would BA usually allow the customer to be rebooked onto the next flight in the paid for cabin?