May I take the Secretary of State back to the comments made by my hon. Friend the Member for Blaydon (Mr Anderson)
and the hon. Member for North Antrim (Ian Paisley) on the impact of changes on the rest of the United Kingdom? Air passenger duty is a case in point. Regional airports in the north of England will undoubtedly feel the impact of any changes to air passenger duty in Scotland. Is that not yet another reason why, as we proceed with devolution arrangements, we need to have a proper constitutional convention so that all measures can be considered across the whole of the United Kingdom?