A London art gallery has come under criticism for exhibiting neo-Nazi artwork and hosting openly racist speakers.

This weekend, artists and campaigners will protest calling for the closure of LD50, in Dalston, east London, after accusations the gallery gave a platform to anti-immigrant, Islamophobic and “alt-right” figures and promoted “hate speech not free speech”.

Guests at LD50’s Neoreaction conference last summer included Brett Stevens, the white supremacist whose writing was an inspiration to Oslo far-right terrorist Anders Breivik, who murdered 77 people in 2011.

After Breivik’s attack, Stevens wrote: “I am honored to be so mentioned by someone who is clearly far braver than I, no comment on his methods, but he chose to act where many of us write, think and dream.”

Others on the conference programme included anti-immigration activist Peter Brimelow, who runs Vdare, described by the Southern Poverty Law Centre as “an anti-immigration hate website” that “regularly publishes articles by prominent white nationalists, race scientists and antisemites”.

Brimelow’s talk at LD50 was orientated around the threat imposed on “native white Americans” by a “great influx of third world immigration”. He said that while it was socially acceptable for Hispanic and Asian ethnic activists to call for more immigration, the only people who get criticised are whites; described the Black Lives Matter movement as a Democratic party racket purely designed to increase turmoil; and referred to the Jewish faction of the Democratic party vote as problematic.

Gallery owner Lucia Diego said in a statement published on the LD50 website that the programme was intended to create “a dialogue between two different and contrasting ideologies” and that the audience for the conference was “very liberal”.

However, a recording of Brimelow’s talk reveals that members of the audience who contributed to the discussion were predominately sympathetic to his views, agreeing with his statement about the need to remove the “corrupt treacherous elite” in government and one professing support for David Duke, the former Imperial Wizard of the Ku Klux Klan and Holocaust denier.

Shut Down LD50 has accused the gallery, which has previously exhibited works by Turner Prize nominees Jake and Dinos Chapman, of curating “one of the most extensive programmes of racist hate speech to take place in London over the past 10 years”. They said the fact that the list of names of the conference speakers had been made public only after the event was finished was telling. “At first in secret, LD50 has acted as a platform for a cross-section of the most virulent advocates of contemporary extreme-right ideology.”

Alongside the conference, the gallery hosted an art exhibition titled Amerika, which explored far-right and Nazi imagery and featured video works of far-right and neoreactive texts being read out by avatars. A pink swastika was graffitied onto the gallery front door last week.

Writing on his ultra-conservative blog, Amerika.org – which is directly linked to on the gallery’s website – Stevens said the neoreaction conference had been held behind a “veil of secrecy to prevent the usual suspects (Leftists and other neurotics) from attacking”.

Last week, in an Facebook exchange with artist Sophie Jung, Diego described the left as “more like a fascist organisation than the real fascists” and indicated her support for Donald Trump, writing: “I’m not even sure if I disagree with the Muslim ban. I see it also as a temporary measure in order for America to get sorted while they transition to another form of government.”

In an open letter, Shut Down LD50 said that it could not “creditably be argued that the talk series was an instance of artistic license or of the free-spirited ‘exploration’ of ideas.

“The fact that the gallerists decided to make the details of their conference public only in late November, after the Trump election victory, is the clearest evidence of conscious purpose”.

Andrew Osborne, a fine art technician at the Royal College of Art, who is among the campaigners, said they would be handing out 2,000 leaflets in the area around the gallery on Saturday to make the public aware of the gallery’s allegiances, adding that the campaign had the backing of businesses neighbouring the gallery. “We believe this is a matter of public safety,” he added.

In her statement, Diego defended the gallery’s programme, writing: “We feel that the exceptionally aggressive, militant and hyperbolic reaction this has provoked vindicates our suspicion that at some point, as a society, we have drifted into a cultural echo chamber.”

She said the reaction of the protesters was proof that anyone who disagreed with the left was “publicly vilified, delegitimated and intimidated with menaces”.

“Our position has always been that the role of art is to provide a vehicle for the free exploration of ideas, even and perhaps especially where these are challenging, controversial or indeed distasteful for some individuals to contemplate.”