Elon Musk's Department of Government Efficiency (Doge) - set up to cut US government spending - claims to have saved, on average, more than $10bn a week since President Trump entered office. "We're talking about almost $200bn and rising fast," Trump told the BBC when talking about Mr Musk's cost-cutting drive on 23 April.

Even as Musk’s work at the Department of Government Efficiency appeared to consume him, his top adviser created a set of companies named Red Planet I, II and III.

Elon Musk said he would keep doing part-time work for the Trump administration beyond next month, raising more questions about his role and whether the White House is following the rules.