I also learned that a Birtish Spy can easily fly to, and fight terrorists in, an American Airport. Furthermore he can call his superiors to have them lock down the airport.
"M, I'm at the Miami airport. There's a bomb here I want you to lock down the airport and send me some support."
"Ok, 00, but you're in America so this will take some time. I have to contact the President and get permission and jurisdictional rights, then I have to fly in the teams and have them pass customs and securities. Should take about 6 weeks, sit tight."