What is the Cabinet Manual – and why are we talking about it now?

Boris Johnson is taking back the power to call elections: John Rentoul on the rewriting of the unwritten constitution

Lord O’Donnell, former cabinet secretary and guardian of our written-but-unwritten constitution (PA)

Britain lacks a written constitution, in that it does not have a single document that sets out in law how the government works, but it does have the Cabinet Manual, written in 2011, which describes the conventions that decide how we are governed.

The manual was drafted by Gus O’Donnell, who was the cabinet secretary, partly because the coalition government was an unusual peacetime arrangement, and partly because it had just passed the Fixed-term Parliaments Act, which changed the long-standing rules about how governments are formed and broken, and how elections are held.

The repeal of the Fixed-term Parliaments Act (FTPA) is expected to be announced in the Queen’s Speech next month, which means that part of the manual will need to be updated. That is why Lord O’Donnell and the most recent cabinet secretary, Lord Sedwill, will be giving evidence to the House of Lords constitution committee on Monday.