But I have been given emails and minutes of various meetings showing how BAA and DfT officials worked hand-inhand. Much of the content has been carefully blacked out. It does, however, give a clear hint of the spirit in which they worked. One meeting minute from November 2006 says "(Blanked name) raised the question of how certain we needed to be by the time of consultation that AQ (air quality) limits could be met." What was the answer? That's blanked out too. But that this question was even raised is worrying: the Government insisted, when it launched its Air Transport White Paper, that Heathrow expansion could only go ahead if "stringent" environmental conditions were met.