Pressure group Labour Leave have been forced to defend their Stoke-on-Trent by-election opinion poll, which put Ukip leader Paul Nuttall in the lead.
The organisation admitted to IBTimes UK that the survey was conducted on Facebook. But a Labour Leave a spokesperson said the poll was a "good sample size, weighted, so while not perfect, we suspect it is strongly indicative".
The survey, of more than 182 people in the West Midlands consistency, estimated that Labour was ten points behind Ukip (25% versus 35%).
"If Labour is to hold onto this seat and others in the Midlands and the North then it must respond to voters concerns over Brexit and immigration," John Mills, the founder of Labour Leave, warned.
But polling expert Matt Singh, the founder of Number Cruncher Politics, raised concerns about the survey. "All indications are that the Stoke poll is garbage. Ignore," he said.
Labour will select a candidate for the by-election from a shortlist of three hopefuls on Wednesday night.
The vote was triggered after Tristram Hunt quit the House of Commons to become the director of the Victoria and Albert museum in London.
The historian, who was first elected to parliament in 2010, won a majority of more than 5,000 votes at the 2015 general election.
But Nuttall is hoping to win over of the 69% of Stoke residents who backed a Brexit at the EU referendum.
Hunt campaigned for a Remain vote, while Corbyn has promised to table an amendment to the government's Article 50 bill, which triggers the divorce talks and will be tabled before parliament on Thursday.
Labour will defend the seat on same day as the Copeland by-election in West Cumbria, 24 February.