In fairness it's not all about the airport, if an airline such as Cathay Pacific chooses to operate into 1 UK airport there's an onus and responsibility on them to have a resiliance plan should they be unable to land at LHR. From all the stories we hear everytime there's an issue at LHR it appears to me that the pilot ends up flying around the UK asking for somewhere to land, they should have a pre-determined plan and agreement with an airport and a handling agent at said airport for such an occourance. Not picking on Cathay by the way just using them as an example.