They could but other destinations and frequencies will have to be dropped such as Manchester.
A decade ago there were around 50 round-trips daily operating between four different London airports and MAN. Today there are just 8 serving LHR only and those are operated by A320-family aircraft rather than the larger B752/B763 types routinely used in the past. Such has been the decline in importance of airlinks to London, crushed by punitive taxation, WCML improvements and more competitive direct offerings by the airline industry itself. Rail and road have taken the P2P business; direct air services to end-destinations and routes via alternative hubs have claimed the rest. Yet despite this massive decline to London in particular, MAN is handling more business than ever before. So the threat of losing more frequencies to LHR is not the concern it once was. Unless British Airways wish to cut themselves off completely from the largest market in Northern England there is little left to cut. And that is a commercial decision for them to make. Life without BA is no longer unthinkable. The market has adapted.
your dogged insistence on utilising figures for the public expenditure to support Heathrow's expansion that have little or no basis in fact.
I use numbers produced by expert professionals published in the public domain. What other kind are available? Neither you nor I will know the final verified figures until many years from now.
You also seem to be focused on the cost of everything and the value of nothing.
As opposed to the value of everything and the cost of nothing as we see from so many other commentators? Both sides of the ledger must be carefully considered.
How much tax (in the form of APD) do Heathrow passengers contribute to the Treasury?
From hub transfer passengers - nothing. From London-originating passengers the same as if they were flying from LGW, STN, LTN or LCY.
How much additional revenue would a 50% increase in traffic generate over 15 or 20 years?
Not enough to justify upto 36 billion pounds in combined expenditure to make it a reality, when LGW can resolve the capacity shortfall for far, far less.
How expensive is that public sector investment looking now?
Honest answer?
VERY!!!
Anyway, until the government of the day grows a paira nd actually makes a decision this debate is rather academic anyway, wouldn't you say?
Much of the media believes that a decision will come in October. If borne out, this debate won't be academic for much longer. The decision-makers need to appraise themselves of the facts now. Time may be short.