Readers of The Sun do not want the newspaper turned into a "Tory fanzine", Lord Mandelson said today.
The Business Secretary seemed relaxed about the announcement from the top selling tabloid that they were no longer supporting Labour.
Lord Mandelson, speaking in Brighton to publicise tomorrow's increase in the national minimum wage, said: "The proprietor might have changed his mind but I don't think the readers want The Sun to set on New Labour.
"The last thing Sun readers want is to see their newspaper turned into a Tory fanzine. They want a newspaper, not a propaganda sheet."
Derek Simpson, joint leader of Unite, who accompanied Lord Mandelson to a hotel in Brighton for the minimum wage launch, said he wasn't surprised by The Sun's announcement today.
"Gordon Brown sounded more like a Labour Prime Minister than ever during his speech to the conference yesterday and obviously The Sun couldn't stomach it.
"This is about as rare as the sun coming up in the morning."