BBC denies emails were manipulated - impossible to know
One thing that is absolutely clear is that unless the BBC stole the source laptop themselves and kept it under lock & key, there is absolutely no way they can know if these emails were manipulated or not.
They can only trust the word of the thief who stole the laptop, a thief who was engaged for the sole purpose of industrial espionage against NDS. Someone who was also enough of a hacker to get past any security Ray Adams had on his laptop. Really not the best of sources.
Of course, this undeniable fact does not stop the BBC spokesman from categorically denying the NDS claims.