I remember those days. I boarded my first BA flight back in the mid 80s on a mobile lounge. They would have multiple lounges boarding at any available door on the plane. I don't remember if they had any boarding order back then.
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by B Watson:
Airport
They were formerly called mobile boarding lounges and docked directly to the aircraft which were parked on remote aprons. </font>