Dominic Raab has been appointed Brexit Secretary following the resignation of David Davis.
The current Housing Minister, who was a big leave campaigner in 2016 EU referendum, will take over from the departing Mr Davis.
Mr Raab will now be facing Michel Barnier in the ongoing EU negiotations that will see the UK leave the European bloc.
The appointment comes after Mr Davis resigned from the position after a Brexit showdown with the cabinet and Theresa May on Friday at Chequers.
In his resignation letter to the Prime Minister, Davis said the "current trend of policy and tactics" was making it look "less and less likely" that Brexit would deliver on the referendum result and the Tory commitments to leave the EU customs union and single market.
He said "the general direction of policy will leave us in at best a weak negotiating position, and possibly an inescapable one".
The "common rulebook" plan "hands control of large swathes of our economy to the EU and is certainly not returning control of our laws in any real sense," he wrote.
"I am also unpersuaded that our negotiating approach will not just lead to further demands for concessions… The responsibility for leading the negotiations should now go to an "enthusiastic believer in your approach, and not merely a reluctant conscript,” he said.