As First Secretary of State, is Dominic Raab the second most senior politician in the UK?

As well as being Foreign Secretary, Dominic Raab holds the office of First Secretary of State, and he has previously deputised for the PM. Surveying this office’s near 60-year history, Stephen Thornton and Jonathan Kirkup explain how its importance depends on who holds the post, and, whatever happens to Raab in any reshuffle, the status of First Secretary can vary according to how the post-holder is perceived by the PM.