The London Mayor has mischievously hinted at an interest in being Prime Minister.
Boris Johnson pointed out to the conference that one French politician had managed to hold the office while still being mayor of Bordeaux.
And the Prime Minister did not seem to mind the idea of Mr Johnson returning to Westminster, as ITV News Deputy Political Editor Chris Ship reports:
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Heavy, thundery, at times wintry showers across the UK overnight tonight and throughout Monday. Feeling increasingly cold.