Anti-racism campaigners have claimed a victory after a leading figure in a far-right German political party cancelled a planned trip to the UK to address the Oxford Union.

Activists had demanded the withdrawal of an invitation to Alice Weidel, whose Alternative für Deutschland (AfD) party has drawn criticism for its links to neo-Nazis. Campaigners had planned to protest during her appearance.

“This is an important victory for anti-racists,” said Kate Douglas from the Oxford branch of the Stand Up To Racism campaign group, which was behind the planned protest. It said the cancellation “shows that anti-racists can make a difference if they organise and mobilise”.

Weidel was due to give a speech to the Oxford Union next Wednesday before facing questions, rather than participate in a full debate. Kristina Kämpfer, a University of Oxford PhD student, co-authored an open letter calling for the event to be cancelled or for its format to be changed in order to subject Weidel to more “comprehensive scrutiny”.

She said: “I fully support the value of free speech but I think the union needs to be aware of the quagmire that’s caused by inviting people like Alice Weidel.” Kämpfer added that the institution had placed itself in the position where it was forced to choose between handing a platform to the far right or denying it one and allowing Weidel to present herself as a victim.

The Oxford Union said: “Alice Weidel has cancelled her planned trip to the UK next week due to concerns with the security arrangements for aspects of her travels and engagements. We regret to inform members that she will therefore not be speaking at the Oxford Union.”

The institution’s president, Stephen Horvath, confirmed Weidel had made no mention to him of any specific threat when cancelling her trip. Weidel and AfD failed to respond to a request for comment and questions on the same topic.

Thames Valley police confirmed it had been working with the Oxford Union on security for the event but was unable to say on Friday evening whether or not it had received any specific complaints or information about security threats.

AfD has made major political inroads since its formation in 2013, becoming the biggest opposition party in the Bundestag. It has capitalised on some Germans’ fears over the recent arrivals of refugees and other people from mainly Muslim countries.

There were reports that Weidel had written that Germany was being “overrun by culturally alien peoples such as Arabs, Sinti and Roma”. She reportedly blamed that on the government being in thrall to the allied nations that won the second world war “whose task it is to keep down the German people”. Weidel denied writing the email, which the newspaper Welt am Sonntag said predated her membership of the party.

AfD has been heavily criticised because of senior members’ links to rightwing extremists, after they marched alongside members of the Pegida group in September.

In response to previous criticism, AfD has said it is a “democratic party which stands up for the constitutional state. The AfD fights against extremists who abuse authorised protests in order to advertise their anti-democratic world view”.

Weyman Bennett, the joint secretary of Unite Against Fascism, said the far right was on the rise globally. “Far right and fascists seek the prestige of institutions like the Oxford Union to legitimise their racist views. Wherever racism is given credibility, it emboldens racists to launch attacks, as was the case in the horrific murder of 11 Jews at their synagogue in Pittsburgh.”