Conservative peer Lord Tebbit has thrown his weight behind a cross-party campaign to get Britain out of the EU.
Lord Tebbit has changed his mind on Europe
The Better Off Out (BOO) group was launched last year by six Tory MPs and claims support from UKIP members and one Labour MP, Austin Mitchell.
Lord Tebbit said he backed British membership of the Common Market, as it was then called, in the 1970s.
But he now felt it was "too diverse" and bureaucratic to work as a democracy and the UK would be better off out.
The Better Off Out campaign says it wants to make the "positive, constructive case for Britain leaving the European Union".
In a statement, Lord Tebbit said: "From being a supporter of British membership of the Common Market in 1970 I have come to believe that the United Kingdom would be Better Off Out of the developing European Republic of the 21st Century.
"We British have a thousand-year history of self government. We have been free and democratic longer than any other nation.
"The European Union is too diverse, too bureaucratic, too corporatist and too centralist to be a functioning democracy," he said.
"We are happy to trade with our European friends and the rest of the world - but we would prefer to govern ourselves."
Lord Tebbit's decision to become a BOO patron could boost its efforts to recruit Conservative MPs - even though they have been warned against joining it.
Conservative leader David Cameron has stopped short of expelling members of the group, even though its stated aim flies in the face of Tory policy on Europe.
John Maples, who controls candidate selection at Conservative Central Office, said "this campaign is contrary to party policy" and the party's leadership would form "a dim view" of any candidate who signs the BOO pledge.