EU referendum: Purdah explained by Prof Robert Hazell

Politicians are using the "purdah" phrase, and debating whether that is a good or bad thing ahead of the planned UK referendum on its future inside or outside the European Union.

But the word is not an everyday phrase, and may leave potential voters scratching their heads.

Professor Robert Hazell, director of the Constitution Unit at University College London, told Edward Stourton on Radio 4's The World at One what this strange word means.

And he looked at how it could affect government "spin" and "good news stories" ahead of the vote.