Attacking “Tory sleaze” will not win the next election for Labour alone and Keir Starmer needs to go on the attack against Boris Johnson, Lord Mandelson has said.

The party grandee told HuffPost UK’s Commons People podcast that while Labour’s local election attacks around “cronyism” and the lobbying scandal will “loosen and crumble” Tory support, it will not be enough to win nationally in 2024.

Starmer must also present a “credible and attractive alternative”, as well as showing Labour is strong enough to “tear [the Tories] inside out, strip them down, lay them bare, and see what they stand for and what they are not doing for this country”.

Mandelson told Commons People: “One thing is clear to me – it’s that Tory sleaze is not going to win the next election for Labour.

“It will loosen and crumble a lot of support for the Tories and people will reach the conclusion that they are out for themselves and that they suit themselves and they fill the pockets of their own cronies and supporters, that’s true.

“But that doesn’t mean to say that Labour’s just got to sit back and wait for the election to fall into their laps.

“That’s not how you win elections. 

“So fine, make the point, but you’ve got to present a credible and attractive alternative if you want people to vote for you.” 

Speaking from Hartlepool where he is campaigning for Labour ahead of the crunch May 6 by-election, Mandelson said the party had a “real fight” in the seat, where it was “completely outgunned” by the combined Tory and Brexit Party vote in 2019.

Johnson is also benefitting from a “vaccine bounce” in the polls, while voters in Hartlepool felt Labour had “lost its way over the last decade” because it was nationally “rubbish” and “fell into bad hands” locally, and that the party took the town for granted.

“Then along came Brexit which loosened the cement even more, and frankly Corbyn then was the final hammer blow for Labour in this town, and then we had the disastrous results in the election in 2019,” he said. 

But now, he said, they feel “Labour is coming home, that there is a new broom, and they feel it nationally with Keir Starmer and I’m glad to say they feel it locally”.

“Increasingly, people are seeing Labour as a credible alternative, they do see Keir Starmer as a man of principles and of integrity.

“But they want to know a lot more about him and what he believes in and what the policies of the Labour Party will be at the next election before they are prepared to transfer their allegiance to him and the Labour Party.

Pointing out that Labour’s leadership has been “hermetically sealed” from the public due to Covid, he said that now the party has to make its case “with greater intensity, and more speed and more focus than we’ve been doing at any time in the last year”.

Asked if Starmer needs to freshen up the shadow cabinet, Mandelson said: “He’ll know what to do when the time comes and I’m not going to start giving him advice or lessons about how he should do his job.

“All I know is this – that people want Labour to make the weather.

“They want Labour to make the news.

“They want the Tories properly taken apart.

“If you fall short, if it’s a bit weak, if it’s a bit flabby, if it appears not to know how to use the media well, if it’s not doing its opposition research well and honing its attacks and creating the ammunition, and [having] people strong enough to fire that ammunition in the Tory direction, then people are going to say well, are Labour strong enough?”

Mandelson went on: “You don’t win elections by going through the motions, you don’t win elections by saying nice things about yourself.

“You’ve got to go for your opponents as well, tear them inside out, strip them down, lay them bare, and see what they stand for and what they are not doing for this country.

“And then people will look to you, and when they do look to you, you better have a credible, affordable set of modern policies for people to vote for.

“And that’s what Labour’s got to create over the next year or so.”

He added: “I want my party to win, I’m fed up of losing, I’m fed up to my back teeth of losing, I want to see my party winning again, and that’s why I’m here and that’s why I work for it.”