Penny drops... Laura K gives us her instant take.
The ex-Chancellor who lost to Liz Truss in the Tory leadership race just seven weeks ago now has the keys to Number 10, after Penny Mordaunt failed to secure the nominations she needed to set up a vote among Conservative MPs.
How did Rishi Sunak get here, what will he actually do as PM and what challenges will be face? Laura Kuenssberg gives us her instant take.
This emergency Newscast was made by Daniel Wittenberg with Chris Flynn. The technical producer was Mike Regaard. The assistant editor was Sam Bonham.