The famous jar appeared in the top left hand corner of the screen while party leader Nick Griffin was addressing viewers in an election broadcast on the web.
The 4.48 minute video then ends with an image of the spread alongside the words "love Britain, vote BNP".
Marmite's advertising is based around the slogan "love it or hate it" - an idea the BNP appears to have been trying to adopt.
A spokesman for Marmite told Sky News Online: "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."
The broadcast - which is still available on the internet - begins with an air-raid siren followed by Mr Griffin telling viewers he will not "flatter and deceive, to promise everything to everyone".
Instead he says he will "tell the truth about the terrible state of our country".
Ironically, Marmite is currently using a fake election broadcast to advertise its product.
The advert - which appears to poke fun at the BNP - features an "election broadcast by The Hate Party".
A spokeswoman for Marmite - which is owned by multinational company Unilever - refused to comment on the advert when contacted by Sky.
Mr Griffin mentions the Marmite advert in a blog post on March 31.
He wrote: "Not being fond of Marmite at all I find it strange this morning that this sticky by-product of the brewing industry should be playing an integral part of my breakfast.
"However such is the case as a couple of early morning calls alert me to the striking similarity between the BNP's 2009 election broadcast and the latest advertising campaign by the purveyors of the brown stuff.
"If you examine this video and the screenshot below from the original you will see exactly what I mean.
"I must say as an exercise in subliminal marketing, just a few weeks before an election, I love it."
Sky News
