DAVID CAMERON cast the Tories into chaos over the EU referendum yesterday after a U-turn befitting TV political satire the The Thick of It.

Speaking at the start of a G7 summit in Bavaria on Sunday, the Prime Minister said the government “isn’t neutral” and would campaign for Britain to remain in the EU.

He added: “If you want to be part of the government you have to take the view that we are engaged in an exercise of renegotiation to have a referendum and that will lead to a successful outcome.”

That was reported across the media as a warning to ministers that they would be sacked or forced to step down if they want to campaign for Britain’s independence.

The PM’s spokeswoman insisted yesterday though that the PM’s comments had been “over interpreted.”

She rowed back on his remarks during a tense government briefing, held in Bavaria but broadcast to journalists in Parliament by phone.

“The PM was clearly talking yesterday about the position on the collective responsibility during the renegotiations,” she said.

“A position that has been over interpreted by a number of outlets this morning, who have wrongly suggested the PM was talking about the approach during the referendum.”

The spokeswoman said no decision had been made by the PM on whether ministers could campaign against the government.

But his statement had clearly caused confusion with his own party.

Even local government minister James Wharton, who as a backbencher brought forward an EU referendum Bill, described the PM’s threat as “reasonable.”

“If the government is taking a government position, if collective responsibility is applied, if you don’t want to support that position, you have to leave,” he told Radio 4 yesterday morning.

The confusion will cast a shadow over the second reading of the government’s EU referendum Bill due in Parliament today.

The bill controversially does not include a period of “purdah” — a period in which ministers and government departments cannot make political statements.

Unlike in the Scottish independence referendum or general election, this means the government will be free to pump out pro-EU propaganda at taxpayer’s expense.