The shadow chancellor, John McDonnell, has blamed the media and internal divisions for Labour’s standing in the polls as the party gears up for a local election campaign that could resurface questions about Jeremy Corbyn’s leadership.

One forecaster has predicted Labour could lose about 125 councillors in elections held across England, Scotland and Wales on 4 May. That would make a third consecutive net loss for the party – an unprecedented run for an opposition party in local polls.

Asked on Sunday about Labour’s ratings ahead of the elections, which span more than 4,800 seats in English county and unitary authorities, as well as councils in Scotland and Wales and some mayoral elections, McDonnell said he agreed with Corbyn that it was partly the media’s fault.

“What Jeremy was saying was the media should now report us accurately and report us fairly,” McDonnell told Sky News’s Sophy Ridge on Sunday programme.



He also said last year’s Labour leadership challenge had caused the numbers to slump. “What’s interesting is when you poll the issues and our policies, they are extremely popular, so what’s preventing people translating that into strength in the polls?” he said.

“It is partly because they see us as divided so if we unite, which I think we are doing now on a number of issues, particularly around Brexit, you’ll see us rise in the polls.”

Jeremy Corbyn on the campaign trail in Leyland. Photograph: Anthony Devlin/Getty Images

The local election analysis, carried out by Robert Hayward, a Conservative peer who is also a respected pollster, estimates a net loss of about 125 seats for Labour, with the Tories and Lib Dems gaining about 100 seats each.

Hayward said Labour could even lose control of Glasgow council and could fall behind the Conservatives in seat numbers on Lancashire and Nottinghamshire councils.

The results could prove to be “a reflection of where the Labour party actually is, which is not appealing to its old core of working class voters across the Midlands and the north, and Scotland”, Hayward said.

If the party performed as badly as predicted in Scotland, he added, it would be “cataclysmic” for Labour, illustrating its 2015 general collapse there had continued.

A mitigating factor could be local issues. As in many areas, Labour in Nottinghamshire is pushing hard on the adult social care crisis, with the council leader, Alan Rhodes, twice writing to Philip Hammond to express alarm at funding levels.

That council represents one of the most bitter fights in the elections, with both Labour and the Conservatives hoping to take control.

Rhodes told the Guardian that Labour has been campaigning on social care and factors such as the impact of HS2. “I am heartened by the campaign, by the hard work of our candidates,” he said. “It is the years of work before that generally determines whether people are going to vote for you.”

One thing that could help the Conservatives is the relative collapse in the efforts and organisation of Ukip since the last equivalent polls, in 2013 in England and 2012 in Wales and Scotland. Candidacy figures for the England and Wales seats showed Ukip is contesting 48% of them, compared with 73% before.

The Lib Dems see this as a potentially limiting factor in their chances of a fightback, especially in the south-west of England, where they hope to take control in Cornwall and Somerset councils.

Gavin Grant, chair of western counties Lib Dems, said: “There is one particular fly in the ointment, which is that the number of Ukip candidates is significantly down, particularly in the south-west. That, potentially, releases some votes back to the Conservatives.”

The Greens, meanwhile, are standing in 54% of seats, up from just under 38%. Co-leader Jonathan Bartley said the party was in a better position than ever before, adding that while local issues dominated, the party was gaining support from Labour – seemingly over Corbyn’s occasionally lukewarm opposition to a hard Brexit.

“I was knocking on doors and people were saying, ‘I was supporting Labour because of Jeremy Corbyn but not any more,’” Bartley said. “There’s been a noticeable change in the past couple of month, especially now the wheels are coming off the Brexit bus.”