Keir Starmer didn't have to quit as an MP as well as stepping down from PM, so why has he? There have been a number of UK prime ministers over the last 10 years - and you have to go back 10 years to find the last prime minister to quit as an MP shortly after leaving as prime minister, that was David Cameron. Tap the link in @BBCNews's bio to read more about Starmer's decision. #KeirStarmer #BBCNews