Sajid Javid is reported to have resigned as Chancellor after a showdown with the Prime Minister and his chief adviser Dominic Cummings.
No 10 demanded Javid sack his advisers if he wanted to stay in post. Javid refused and quit.
Former Chief Secretary to the Treasury Rishi Sunak has been appointed to replace Javid at No 11.
There will now be a joint special adviser team across No 10 and the Treasury.