Let us suppose that LCY sees a big expansion in transatlantic business-only flights.
What effect does this have on flights from LHR to the eastern seaboard ?
Presumably if Odyssey launch from LCY, then BA will have a competitive response from LHR - at least until Odyssey are squished or BA decide to stop the blood letting and accept Odyssey as a competitor.
Now suppose that BA launch a significant expansion of transatlantic from LCY. What happens to the flights from LHR to the same destinations ? Is LCY really just a metaphorical drop in the ocean with plenty more demand for transatlantic business class seats anyway, or is this going to make a big dent on profitability by part cannibalising existing transatlantic flights from LHR ?