https://www.britishairways.com/conte...unges/arrivals says:

• British Airways customers arriving in First or business (Club World) cabins.
• British Airways Club Gold members arriving on a long-haul British Airways flight.
• American Airlines Emerald Tier card holders arriving on a long-haul British Airways or American Airlines flight.

Personally i will miss the gold line for when ba foul up or hit issues, which they have done more than once a year or so in my case. Though even the gold line often don't know their rules (eg guf use). I figured best to just cut the cord. May manage owe on aa.