A leading Conservative MEP has hit out at "anti EU Taliban" members of the party who are desperate to quit Brussels.
Sajjad Karim said elements within his party were so determined to leave the EU they were presenting a "skewered view" of the debate.
In a Twitter debate on Tuesday, he twice used the term "anti-EU Taliban" about those who are determined to push for an exit.
Later, he told The Huffington Post UK: "I have not used that term lightly, that's exactly what they are.
"You are no longer allowed to hold a view unless it's the same view as them."
Karim, the MEP for the North West and the Tories' legal affairs spokesman in Europe, agreed that many of the people he referred to were in his own party, but insisted it was a minority.
The dispute threatens to once again disrupt Tory unity on Europe, after MPs left for their summer break delighted at the party's referendum stance.
It also comes after the first of a series of reports, looking at which powers are retained by the UK and which are controlled by Brussels, was published.
The Balance of Competences review will form the foundations of David Cameron's attempts to win back powers ahead of the promised in/out referendum in 2017.
The report was instantly branded a "whitewash" by Eurosceptic Tory MPs, who claimed the picture it painted of life in the EU was too positive.
But Karim, who has been working on proposals on reforming the EU, including cutting red tape to business, hit back.
"The first set of reviews is not what they want, so automatically they have come out and rubbished it," he said.
"If you, like some of us, have invested months and months of time that you don't have, to carry out an independent constructive exercise, you present it, and automatically those people who have done nothing whatsoever, they stand on the sidelines and have a hoot at you."
It is no wonder Britain doesn't have enough influence in Europe with such an attitude, Karim said.
Anti-EU supporters don't want to have a debate on the facts, he said, and instead Britons to make a decision "in blissful ignorance".
The "savvy" British public would make up its own mind, he said, but warned that if the referendum was close either way, "I'm afraid the debate doesn't go away."
Tory MP Douglas Carswell, who wants to quit the EU and was one of the critics of the balance of competence review, said he did not want to respond to the "anti-EU Taliban" jibe.
He added: "I believe we should withdraw from the EU, I will face my electorate accordingly, and ultimately they must decide whether they believe, as I do, that Britain should leave the EU, or as Sajjad does, that we should remain in."
Tory right-wingers have recently objected to the label "Tory Taliban" after they proposed a string of new laws, including a Margaret Thatcher day and banning the burkha.