Most of the media attention surrounding next week’s byelections has been on a certain seaside town in Essex, where Douglas Carswell will aim to keep his Clacton seat after defecting from the Conservative party to the UK Independence Party (Ukip).

But 250 miles north-west, another fraught electoral battle will be decided on the same day. The voters of Heywood and Middleton in Greater Manchester will select a new MP following the death of Jim Dobbin last month.

Labour currently has a majority of 6,000, but Ukip senses an outside chance of victory. The odds are certainly shortening: last week bookmakers Ladbrokes had a Ukip win on 20-1, but on Thursday that had narrowed to 9-2. (Labour is still the clear favourite, at 1-8).

More households in the predominantly white, working-class seat have put up posters in Ukip’s yellow and purple colours than the party ever dreamed possible, and outside the shopping centre in Middleton on Thursday morning it was difficult to find anyone who claimed they were certain to vote Labour on 9 October.

“I’ve voted Labour all my life and never, ever again,” said one angry woman. “We have been utterly deserted up here. Our properties are worthless, our jobs have been taken by foreigners and they are only interested in what happens down in London.”

During the Labour party conference last week, one of Manchester’s Labour councillors put out an SOS call. Peter Cookson, who represents Gorton South, pleaded with delegates at a fringe meeting to “come and help us” in Heywood and Middleton. “Ukip are a real threat there,” he said.

No wonder Ukip’s irrepressible leader, Nigel Farage, made his second visit to the constituency in as many weeks on Thursday morning. Two hours later, Ed Miliband was due to go on the stump too, outside another shopping centre in Middleton: he knows this is a byelection Labour can’t afford to lose.

Ebullient as ever, having obliged the snappers by chomping down on a bacon butty, Farage said he thought Ukip might just squeak it. “What we know is that we are rapidly moving. We’ve got the momentum with us, and Labour are clearly very worried indeed, but we’ve only got a week to go and there is a mountain to climb,” he said.

The seat, or various incarnations of it, has been Labour for the past 50 years, ever since housing estates were built to relocate thousands of poor residents from central Manchester back in the early 1960s. A Ukip victory here would change everything for Miliband’s party, said Farage. “It would mean that the dam is burst and the one-party Labour state that much of the north of England has become has a real challenger. It’s already happening – in the European elections there was a large part of the north where we topped the polls, but that was ignored by Westminster-based journalists because it doesn’t suit their agenda.”

He refused to apologise to those who claimed he was making political capital out of the child sexual exploitation scandal which has engulfed nearby Rochdale, insisting such crimes proliferated as a “direct result of policy failures” by the local Labour party. In 2012 a sex-trafficking gang of men of mainly Pakistani origin were found to have preyed on at least 47 girls, who were all white.

Ukip’s candidate, John Bickley, a 61-year-old businessman, said the number one issue on the doorstep was immigration. Sometimes it’s because people are worried about the pressure on jobs and housing and local services, he said. “But often it’s more of an umbrella under which comes everything which expresses their detachment from Westminster politics.”

Wrenching lifelong Labour voters away from the party isn’t always easy, he conceded. “But so often I can see it in their eyes that they want to come with us. I liken it to an abusive relationship. They know they’ve been abused and ignored by Labour for years and yet Labour keeps saying they care, and so they can’t escape. I would hope that we could be some sort of shelter for them.”

Colin Kirby, 63, a thoughtful retired teacher, admitted he was considering defecting from Labour to Ukip, fed up of what he called Miliband’s “Londoncentric” politics. “There’s no clarity between the two main parties, so when you hear something different, it’s attractive. Essentially I’m a Labour voter, but a disenfranchised one. The dynamic of Labour is so narrow, so Londoncentric. All of the main decisions about important things in the north of England are taken down in London.”

Originally a Scouser, Kirby now lives in Alkrington, one of the wealthiest bits of the generally deprived constituency. “I suppose it’s what you might call a nice middle-class area, with a mix of Labour and Tory voters,” he said. “But from the conversations I’m having in shops and pubs, I think Ukip could be in with a chance.”