I do think the OP has a point even if it was not expressed very well initially. He knew his flight was delayed and asked to be transferred to an earlier one. This seems to be a very reasonable request. While accepting that BA was within its rights to deny the transfer it would seem fair to do so. I have requested such a chamge several times when flights have been delayed and the request has been granted every time.

What the responding posters seem to be saying is that BA can delay a flight but a request to mitigate the delay is unreasonable. Come on folks you can't all work for BA!