Downing Street is trying to exclude Nicola Sturgeon and other political leaders from TV debates on Brexit.

David Lidington, Theresa May’s de facto deputy, said this morning that it was a debate “between the leaders of the two biggest parties at Westminster”, suggesting that No 10 want to avoid her coming face to face with anyone other than Jeremy Corbyn.

This raises questions of representation which could complicate broadcasters’ plans to hold a debate.

Mrs May and Mr Corbyn broadly agree on the shape of Brexit, since they both are committed to leaving, ending free movement and leaving the single market. They disagree on the customs union, and Labour rejects Mrs May’s deal for failing to preserve the “exact same benefits” as EU membership, something