Protesters are to gather outside BBC headquarters tomorrow as the British National Party's election broadcast is aired.
The BBC is accused by campaign group Unite Against Fascism (UAF) of giving "unwarranted and uncritical coverage" of the BNP during the run-up to the election.
The BNP's five-minute party election broadcast (PEB) is set to be aired on BBC1 at 6.55pm.
UAF's protest at Broadcasting House in central London will be supported by the Broadcasting, Entertainment, Cinematograph and Theatre Union (Bectu), as well as the Muslim Council of Britain and Jewish Council for Racial Equality.
A BBC spokesman said the Corporation was "obliged to treat political parties contesting the election with due impartiality", as set out in its charter.
He added: "Over the course of the election, we will ensure appropriate scrutiny as we would with any party."
But UAF joint secretary Sabby Dhalu said: "The BBC has given unwarranted and uncritical coverage of the BNP during this election campaign, particularly on TV news and Radio 4, which has failed to challenge its racist scapegoating of immigrants and Islamophobia.
"The BBC's justification for giving the BNP more coverage is the election of two BNP MEPs last year. This is misguided.
"Giving the BNP a platform and failing to expose and challenge it gives the BNP a veneer of legitimacy.
"The BNP is a fascist organisation, not a normal political party, and the public does not pay its licence fee to see fascists broadcast their politics of hate."
Gerry Morrissey, general secretary of Bectu, said the BNP's policies were "abhorrent to the vast majority of hard working people".
He said: "The BNP would like to scare people to believing they have something to fear from multiculturalism, and their policies of hatred and racism should not be given airtime by our broadcasters."
BNP leader Nick Griffin's controversial appearance on Question Time in October led to the BBC Television Centre in west London being "locked down" due to a surge of protesters.
Campaigners brought traffic to a standstill as they demonstrated against the decision to invite him on the flagship current affairs programme.
Launching the party's 90-page election manifesto last week, Mr Griffin said: "We say Britain is full. It is the most overcrowded country in Europe and it is time to shut the doors."
Mr Griffin, a parliamentary candidate for Barking, east London, recently came under fire from the owners of Marmite after the BNP featured a jar of the savoury spread in an online preview of its PEB without permission.
In the online version, Mr Griffin sits at a desk in front of a framed photograph of Sir Winston Churchill.
He tells viewers: "I will put British people first all the time, every time, and I don't care what the politicians and media liars say because of it.
"I tell the truth. So don't waste your vote - do the one thing that will really upset politicians: get your own back.
"Get up, get out and vote British National Party - then they will listen."Reuse content