The Electoral Commission will consider whether to investigate pro-Brexit material which was distributed in Peterborough.
The regulator has received a complaint about leaflets and a poster which promote Britain leaving the European Union.
The complaint centres on leaflets not carrying an imprint and a poster being placed on an empty shop which does not belong to the campaigners responsible.
An imprint is added to election material to show who is responsible for its production.
According to Electoral Commission rules: “On printed material such as leaflets and posters, you must include the name and address of: the printer, and the promoter.”
Matthew Mahabadi, who is coordinating the Labour IN For Britain campaign in Peterborough, said: “This disrespect for the electoral process and for the people of our area is underlined by the totally ludicrous and divisive claims being made both on the offending leaflets and posters. No wonder so many local voters are questioning whether they can trust any of the Leave campaign claims made to date.”
Jay Beecher, deputy chairman of UKIP Peterborough and VoteLeave co-ordinator, said: “The leaflets in question aren’t official VoteLeave Campaign material. I can confirm that every leaflet we hand out fully complies with all legal requirements.
“The VoteLeave campaign in Peterborough is proving extremely popular and is gaining in momentum. This is clearly just a desperate and futile attempt by the few who represent the Remain campaign to throw a spanner in the works.”
A spokesman for Leave.EU said the leaflets definitely had nothing to do with them. He added: “Posters we normally print are on a tarpaulin with rings in the corners to allow them to be tied to a table for street stalls. I will pass this on to our events team so they can investigate this further.
“We have thousands of people volunteering for us across the country so it is impossible to monitor all of the activities they may be carrying out without our knowledge.
“We do not condone this sort of behaviour. We will be disappointed if it turns out that our activists are responsible for this.”
A spokesman for the Electoral Commission said: “We are aware of this issue and are considering this in line with our established enforcement policy.”