London, England - Thousands are expected to join an anti-racism march in London aimed at protesting against far-right groups in the UK and Europe.

The Stand Up To Racism event, scheduled to begin in central London at 12:00GMT on Saturday, will see campaigners and activists calling out institutional racism against migrants and ethnic minorities.

Demonstrations are expected to spread across the UK and European Union, with marches planned in Cardiff and Glasgow, as well as Paris, Berlin, Vienna, Amsterdam and Athens, coinciding with the United Nations' International Day for the Elimination of Racism and Discrimination.

The event comes after Mark Rowley, who recently retired as the Metropolitan Police's counterterrorism chief, warned that the far right poses an "organised and significant" threat to the country, as he revealed four far-right "terrorist" plots had been foiled since the beginning of the year.

According to Hope not Hate, Britain should brace itself for more far-right violence, claiming that 28 people were arrested or convicted for far-right inspired "terrorist" offences in 2017.

These include Darren Osborne, a white Briton who was sentenced to at least 43 years in prison after killing one person and injuring 12 as he drove a van into a crowd of Muslim worshippers outside a mosque in Finsbury Park in June.

Osborne regularly read material from former English Defence League (EDL) leader Tommy Robinson and the far-right Britain First group, among others.

A year earlier, in 2016, far-right gunman Thomas Alexander Mair killed Jo Cox, a Labour MP. Mair said he saw Cox, who was anti-Brexit, as a "traitor to white people".

Brexit effect

According to a UN report, "divisive, anti-immigrant and xenophobic rhetoric" during the EU referendum campaign triggered a surge in hate crimes following Britain's June 2016 vote to quit the bloc.

The year between 2016 and 2017 saw the largest percentage increase in hate crimes since 2011 to 2012, with the number of reported offences rising to 80,393. The majority of those offences - 78 percent - were racially motivated.

When one commits an act of terror, not all white people are seen as suspects. This is where we need to understand the differences in how Islamists and the far right are treated. Aaron Winter, professor

"[It is] no coincidence that at a time when we have Brexit and increased mainstream xenophobia, the far right is emboldened," Aaron Winter, professor at the University of East London and member of the university's terrorism and extremist centre, told Al Jazeera.

"An increase in the far right and hate crime has been linked to the environment and atmosphere around Brexit, which has normalised and mainstreamed Islamophobia and racism in the media and by politicians."

Winter said this has an effect on policy-making, paving the way for widely reported cases where "people get stopped at the borders and treated as though they don't belong to the country".

He accused the government of having "double standards" as "homegrown far-right extremists are treated much differently from Islamists".

He explained that the far right enjoys significant media attention and is able to infiltrate the political landscape.

"Also, when one commits an act of terror, not all white people are seen as suspects. This is where we need to understand the differences in how Islamists and the far right are treated, but also where the double standards are."

While Hope not Hate claims membership of far-right organisations in the UK is at its lowest in 20 years, an online presence is growing.

Labour MEP and Chair of the Civil Liberties, Justice and Home Affairs Committee, Claude Moraes, is expected to address protesters at Saturday's march.

He told Al Jazeera: "[The] significant threat of neo-Nazi and far-right terrorism in the UK [means it is now] thoroughly on the radar of British authorities."

Moraes said the threat stems from a "very strong populist wave based on anti-Muslim, anti-refugee rhetoric and an increasingly anti-Semitic one", coupled with "hardcore trends of the far right".

Europe has recently witnessed far-right parties such as the Freedom Party in Austria, France's National Rally - formerly known as the National front - and AfD in Germany gain popularity.

"The huge development of the far right actually being in government now is an existential threat to the EU, people of colour and minorities, but is also disruptive to EU societies because it creates divisions between people," said Moraes.