Originally Posted by
prometa
The London arrivals lounge is such an excellent perk of flying Polaris that I'm surprised other major UA international destinations don't offer one. Perhaps London is the only place where enough overnight flights land in the AM, with enough passengers having it as their final destination to make it worth it.
LHR arrival lounge is also partly funded by AC for their passengers to use. So between UA and AC, they probably have enough arriving J (and some elites) to use the lounge.