In the case of BA when disruption is expected in LHR, they do inquire with the stations that handle BA on a daily basis what their ability is likely to be if asked to handle diverts. A report has to be submitted to BA which includes information like staffing levels, hotel availability, Stand availability, De-icing capability, coaching availability and equipment availability. In terms of stand availability, the airport stated that up to 5x narrowbodies and 2 x widebody a/c could be accepted although only one widebody could be accepted by the handling agent due to only having one set of widebody steps on station, hence there being pics on the internet with the BA 767 with steps attached and the AA 767 without steps attached.