A member of the British National Party from Preston has been accused of infiltrating a university campus to distribute "offensive" material.
An investigation has been launched into BNP member Tony Bamber, who has previously been accused of distributing anti-Muslim leaflets across Preston.
Police have been contacted and campus security tightened, after Mr Bamber, allegedly infiltrated the University of York mail system to deliver the leaflets.
University staff received leaflets issued by Mr Bamber, who is suspected of accessing the mailroom by pretending to be a member of staff.
A university spokesman said: "Many staff found this material offensive, and we have sent copies of the various letters to the police.
"We deplore the underhand use of the university's internal mail system, whose working practices have now been changed to guard against any repetition."
Mr Bamber, 52, who stood in local elections for the BNP in the Tulketh ward in Preston in 2006, confirmed he produced and distributed the leaflets, but denied impersonating anyone.
He admitted that he visited the university mailroom, but says he was was not asked who he was.
He distributed at least two different leaflets, one of which accuses Britain's political leaders of failing to defend Britain's economy, culture and says they have failed the nation by allowing Muslims to create "large and hostile colonies".
A police spokeswoman said: "We are aware of the allegations and have started an investigation."
Mr Bamber told the Citizen he would continue to distribute the leaflets as he had not been charged and therefore was not doing anything illegal.
Mr Bamber is already being investigated by the Hate Crime Diversity unit at Lancashire Constabulary.
The question of whether the leaflets amount to incitement to religious hatred is being considered by the Crown Prosecution Service.