An alleged neo-Nazi student sent material about the fascist leader Oswald Mosley to his parents, a court heard.
Andrew Dymock, 23, from Bath, is on trial at the Old Bailey charged with 15 terrorism and public order offences.
The court heard his father, an academic, had requested he did not send "political stuff" to his work email for fear of his colleagues thinking he "sympathised with fascist views".
The defendant denies all the charges.
The court was told Mr Dymock emailed his parents in May 2017 with a video called "Oswald Mosley Documentary - Multiculturalism".
In response, his father Dr David Dymock said: "I work in a multicultural institution, am proud to do so and believe in the values of that institution.
"I would hate anyone who might see my emails to think that I sympathised with fascist views in any way."
The jury heard that Mr Dymock's mother Stella responded by writing "Not what I expected. Thoroughly illuminating".
Mladic 'did nothing wrong'
Mr Dymock is alleged to have been part of the now banned groups System Resistance Network (SRN) and Sonnenkrieg Division, and to have used the SRN website and Twitter for extremist posts.
One tweet from the SRN account on 23 November 2017 praised Bosnian Serb leader Ratko Mladic the day before he was convicted of war crimes, saying he was a "hero" and describing Muslims as "Islamic scum".
A graphic taken from the Twitter account featuring a rainbow flag, an EU flag, an Israeli flag apparently on fire and a United States flag matched one found on a laptop discovered by police at Mr Dymock's address, the court heard.
An image of Adolf Hitler featured in a tweet from October 2017 stating "The Racial Holy War is inevitable. Hail Total Aryan Victory!" was found on the same laptop, the court heard.
Mr Dymock denies five counts of encouraging terrorism, four of disseminating terrorist publications, two of terrorist fundraising, one of possessing material useful to a terrorist, one of possessing racially inflammatory material, one of stirring up racial hatred, and one of stirring up hatred on the grounds of sexual orientation.
The trial continues.