Police are looking at a Tory candidate's marketing material after complaints he is pretending to represent Labour.
Robert Largan is defending a majority of under 600 in High Peak, making it one of the top targets for Keir Starmer.
But he has faced a backlash after posting images on social media with a striking red background and the message 'Labour for Largan'.
A similar post states 'Reform for Robert' with the insurgent party's cyan colour scheme.
Mr Largan insisted he had done nothing wrong, and even taunted opponents on social media by highlighting the Reform image.
Police are looking at a Tory candidate's marketing material after complaints he is pretending to represent Labour
Derbyshire Police posted on X in response to complaints about the marketing material
Robert Largan is defending a majority of under 600 in High Peak, making it one of the top targets for Labour
Mr Largan captioned the message with the red background: 'So many local Labour voters have told me they're going to vote for me, because they want to keep me as their local MP.
'There have been so many that I'm launching a new Labour for Largan club.'
Critics suggested Mr Largan could be breaching electoral laws, but the Tories insisted the material 'clearly carries imprints' of the party he represents.
On the bottom left corner of both images are the words: 'Promoted by Jason Mcleod on behalf of Robert Largan, of High Peak Conservatives, 1a Hardwick Mount, Buxton, SK17 6PP.'
Derbyshire Police posted on X: 'We wish to confirm that we have received a number of messages in relation to claims of election fraud, raised due to concerns around marketing material. An incident has been created and will be reviewed.'
A spokesman for Mr Largan told the BBC: 'As Mr Largan's social media posts and website make abundantly clear, large numbers of traditional Labour voters have been contacting him to tell him they plan to vote for him, despite him being a Conservative candidate.
'The same goes for Reform supporters - this is because of Mr Largan's strong record of delivery in the High Peak.
'Therefore, supporters clubs of traditional Labour and Reform voters have been set up, to allow people to tell Mr Largan that they're supporting him.
'These are called Labour for Largan and Reform for Robert. Such supporters' clubs are not a new phenomenon.'
A similar post states 'Reform for Robert' with the insurgent party's cyan colour scheme