UK Airports News reports WW as also saying:

He added that BA was committed to expanding services to the US, where demand remained robust despite the economic downturn. BA already runs a service to New York from London City, via Shannon in Ireland, targeting business customers. Mr Walsh said: ‘We have two aircraft there, and if it continues the way it has we will definitely look at additional services.' He said it was ‘only a matter of time’ before the airline expanded its transatlantic services from other airports too.

I take this more of a threat to LHR than any serious intent to offer transatlantic services from other airports (apart from his stated intention for LCY). Would be ironic having recently cut the MAN-JFK service and a half-hearted attempt at MAN-LAX some years ago.