Boris vs Barack in the EU referendum campaign

As the EU referendum campaign wears on, the rules of engagement from both sides are becoming clearer – or at least the rules that both sides would like to use for engagement. The Inners are in favour, unsurprisingly, of throwing everything they can at the campaign to keep Britain in the EU. The Outers are annoyed that the Inners are doing this, though their surprise often seems exaggerated: they cannot really be shocked that a government would try to do everything to stop a change that it thinks is a bad thing for the country.

Today Boris Johnson sets out one of the rules of engagement that Brexit campaigners would like to see, which is no foreign governments being dragged into this. Eurosceptics were furious recently when François Hollande and French economy minister Emmanuel Macron made interventions about the border between France and Britain.