Gary Lineker has challenged Twitter boss Elon Musk over a threatening message sent to his son in the wake of the TV presenter's row with the BBC. The Match Of The Day host - who was reinstated on Monday - tweeted a screenshot of a private message sent by a user describing his son, George, as a "mug" who needed to be "burned at the stake" for defending his father. Lineker wrote with the image: "Is this acceptable @Twitter @elonmusk? And I don't mean the grammar." Earlier in the day, George had tweeted: "Social media's mad isn't it. Over the...