Fake news!
Why do I say so? Because
(a) any such a major new story would be referenced on the relevant BBC page
https://www.bbc.co.uk/news/topics/cywd23g045pt/sadiq-khan ; and
(b) the Government don't have the power to remove, or restrict, a democratically-elected official anyway
That page has simply embedded the content of this one, which is as about as biased and untrustworthty as it's posible to get:
https://taxileaks.blogspot.com/
Although my political views are generally to the right of Maggie Thatcher's (and even, often, Adolf Hitler's), I generally think that Sadiq Khan has been doing a great job for Londoners.