Annunziata Rees-Mogg, who has twice stood as a Conservative general election candidate, said she had chosen to join the Brexit Party because she believed Theresa May had “betrayed democracy” by failing to implement the result of the referendum.
She was unveiled by Mr Farage as he warned that his new venture would “put the fear of God” into MPs by topping next month’s poll.
Ms Rees-Mogg said: “Our politicians need to listen to what the people have said. I joined the Conservative party in 1984. This is not a decision I have taken likely. To leave a party for which I have fought in every election since 1987, from Maggie Thatcher through to Theresa May.
“We’ve got to rescue our democracy, we have got to show that the people of this country have a say in how we are run. That the politicians are not our masters, they are to do our bidding. We must fight back not only of control from the European Union but fight back for control of our own democracy. The stakes are that high.”
Ms Rees-Mogg, who last stood as a candidate in 2010 in Somerset and Froome, when she lost by 1,800 votes to the Lib Dems, said she had been driven back into politics because she could not longer “put up with the despondency on the streets”.
She added: “I cannot bear to see the anger amongst the people this country’s elected members have ignored. We must fight their fight, we must win the fight, and we must leave for a greater future and better politics.”
Former Conservative donor Ben Habib was also announced alongside Ms Rees-Mogg as one of 70 candidates who will be fighting the 23 May elections to the European Parliament if Mrs May is unable to get a Brexit deal through Parliament before then.
Mr Farage said he had placed a £1000 bet on his party winning the most seats in the upcoming contest, and said the group would be “the most impressive list of candidates any political party has put before the British public in history”.
“I said many years ago that I wanted to cause an earthquake in British politics, well now what I am fighting for, and with your support what we will attempt to achieve is a democratic revolution in British politics becuase that is what we need,” he added.
And Mr Farage, who has served as an MEP for the past 20 years, also used the speech to blast “career politicians” who fell back on the “safety net” of European politics.
He added: “I said many years ago that I wanted to cause an earthquake in British politics, well now what I am fighting for, and with your support what we will attempt to ahcieve is a democratic revolution in British politics becuase that is what we need.”