The British National Party and the owners of Marmite have become embroiled in an acrimonious row, with threats of legal action and official complaints.
Unilever said it was "initiating injunction proceedings" after the BNP featured a Marmite jar in an online version of its General Election broadcast without permission.
But the BNP said the logo had been used in retaliation to Marmite adverts featuring the spoof "Hate Party" - which the BNP claims is "clearly based" on them - and it was complaining about Unilever to the police, Electoral Commission, Independent Television Authority and Advertising Standards Authority.
The battle erupted after a preview of the BNP's broadcast on the party's website featured a Marmite jar in the top left-hand corner of the screen whenever party leader Nick Griffin was addressing viewers. It was still publicly available on Thursday morning but was later removed - though it remains on the video-sharing website YouTube.
Unilever issued a statement saying: "It has been brought to our attention that the British National Party has included a Marmite jar in a political broadcast shown currently online.
"We want to make it absolutely clear that Marmite did not give the BNP permission to use a pack shot of our product in their broadcast. Neither Marmite nor any other Unilever brand are aligned to any political party.
"We are currently initiating injunction proceedings against the BNP to remove the Marmite jar from the online broadcast and prevent them from using it in future."
A series of Twitter messages from Mr Griffin, who is an MEP and standing for election in Barking, east London, were posted on the BNP website about the row.
"Unilever PR men and lawyers all over us like a rash," he said. "Very upset at our using Marmite in our TV broadcast. They should have thought of that before modelling the one for their Hate Party on us."
An article later appeared on the BNP website claiming that a "joker" had amended the broadcast to include the Marmite jar. "The official broadcast contains no mention or images of Marmite at all," Mr Griffin said.