The editor of the Daily Telegraph newspaper has sent a mass email to readers on its database and told them to vote for the Conservative party.

Chris Evans took the “unprecedented step” of writing to everyone on its email database who had ticked “agree to receive marketing messages by email from Telegraph Media Group”.

“Do we continue under the Conservatives with the open, enterprise-led economic approach that has underpinned our prosperity for nearly 40 years?” the email read.

“Or do we revert to an old-style, ‘government-knows-best’ culture championed by the most leftwing Labour leader for a generation?”

The letter ends: “The Daily Telegraph urges its readers to vote Conservative.”

The newspaper has endorsed the Conservative election and released a front page this morning with the heading “Don’t do something you’ll regret”.

Another story on the front page carried quotes from a major Ukip donor asking conservatives considering a Ukip vote to reconsider.

The email was set out overnight and polls were not open at the time.

In an interview published yesterday Labour election guru David Axelrod said criticism by the Conservative-supporting press had actually boosted Ed Miliband’s status in the polls.

“I think you need to tolerate that noise. In certain ways it’s worked to Miliband’s advantage,” he told US website Politico. “When he emerged in the campaign and performed well, he completely surpassed the expectations that were set for him.

“He wasn’t the cartoon that the conservative media had depicted him as. He took four years of beatings from the conservative media that lowered the bar which he then cleared smartly.”

Mr Miliband’s personal ratings have risen significantly since the start of the election campaign, which also marked the intensification of personal attacks against him in some newspapers.