Remember the days when BA had a reciprocal FFP deal with EK? THey also code-shared IIRC on AUH-LHR and DXB-MAN. Pulled the plug about 6 years ago but not sure who initiated.

It's tricky. If I were BA I wouldn't want any of these rather formidable competitors in OW (especially not EK) so as not to take away traffic from me. Unless of course there were a danger of them joining Star.