The ERG, a hard Brexit backing group of Tory MPs, is adamant on ensuring Britain makes a success of Brexit.
Now with Mr Rees-Mogg at the helm, the group is likely to push for a clean break from Brussels after the Somerset MP told Mrs May to stick to her negotiation ‘red lines’ last month.
Mr Rees-Mogg’s promotion from vice-Chair could also bode well for the trailblazer’s future – with both of his predecessors later finding roles in the Department for Exiting the European Union.
In a statement, Mr Rees-Mogg said: “I am delighted to have been elected in succession to Suelle Fernandes and Steve Baker who were both superb Chairmen.
“In this role I am keen to help the Government implement the principles laid down by the Prime Minister, Mrs Theresa May, in her Lancaster House speech.
“It is especially important to achieve control of our laws, control immigration and achieve new trade agreements with other countries.
“The ERG speaks individually, not with the collective view, but has considerable support across the Parliamentary Party.
“As Chairman I intend to be helpful, vigorous and supportive towards Government policy of making a success of Brexit.”
The ERG was instrumental in convincing Tory MPs to turn against David Cameron and support BRexit during the EU referendum.
Mr Rees-Mogg said: ”The ERG has an important role to play in representing back-bench eurosceptic views both to the Government and the wider public.
“There is a strong desire to ensure that the positive emphasis of Brexit is maintained and we focus on the ambition of Brexit to create a more prosperous Britain rather than being bogged down in the minutiae of negotiations.”
The ERG are expected to take the fight to the Cabinet as several members of MRs May’s top team attempt to soften the terms of Brexit.
Speaking to the Telegraph, a senior ERG Eurosceptic said: “We are going to look at Cabinet members and make them stand up for Britain.
“There are a lot of things that need to be argued for as we enter the next phase of negotiations.
“We must be at the forefront of the debate.”