More than 1,000 advertisers have pulled out of advertising with far-right news outlet Breitbart, a campaign group has claimed.

Kelloggs, BMW, Visa, T-Mobile, Nordstrom and Lufthansa have all severed ties with the company over the last few months, according to a database from Sleeping Giants.

A petition for Amazon to cancel its relationship with the website has also reached almost half-a-million signatures.

A total of 1,132 companies have so far pledged to remove the ultra-conservative site from their media plan, Sleeping Giants said.

Emma Pullman, lead campaign strategist at separate campaign group SumOfUs, told The Independent that most of the companies were pre-existing advertisers.

Some had put the website on their black list after accusations it writes misogynist and racist articles, she added.

“We are reaching fever pitch," she said.

She added: "The idea behind the campaign is if we can convene enough people we can interrupt its ability to expand.

"The campaign is symbolic. This is a really tangible way people can convince companies to not advertise and it's also a way to criticise the rise of the far-right and the hatred, xenophobia and racism that is coming out of Breitbart."

Stephen Bannon, former executive chair of Breitbart and now Donald Trump's chief strategist, boasted last year that the website was a "platform for the alt-right”.

As Breitbart aims to expand around the world, people are buying up URLs like Breitbart.fr to make it more difficult.

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Large German companies like BMW, restaurant chain Vapiano, Deutsche Telekom and Lufthansa have cut ties.

Lufthansa said its decision was due to Breitbart's "violent, sexist, extremist and radical political content".