The Survation poll ahead of the May 6 count places Northern Independence Party (NIP) candidate Thelma Walker on 6% along with independent rival Samantha Lee.
Conducted for ITV’s Good Morning Britain, it puts Tory Jill Mortimer on 50% – 17 points ahead of Labour’s Dr Paul Williams in a seat which has remained red for 57 years.
Green candidate Rachel Featherstone is fifth on 3% with Liberal Democrat challenger Andy Hagon and Reform UK’s John Prescott each on 1%.
A NIP spokesperson said: “To be polling at 6%, decisively ahead of the Green Party and Liberal Democrats in a first past the post election which inherently favours established parties, is an astonishing
achievement both for Thelma and for the barely six months old Northern Independence Party which is endorsing her.
“Fieldwork for the poll was conducted over a period stretching back as far as 10 days ago and reports coming back from our volunteers in Hartlepool suggest that we have been consistently gaining ground since then.
“This poll may underestimate our support.
“This is a breakthrough moment, and a clear indication of the appetite Northerners have for a party proud of its democratic socialist politics, created by Northerners to stand up for the North.
Meanwhile, independent candidate Ralph Ward-Jackson warned: “There is a feeling that voting in a Tory MP will bring untold economic advantages to the town.
"On the contrary, a weak MP with no clout in London will be ignored by a Treasury which is starting to run out of money to spend.”