Cuillin, 6 and Leija, 4, will unveil the plaque as part of a Great Get Together day.
Increased action against far-right extremists follows the murder of MP Jo Cox by a white supremacist.
The Great Get Together aims to unite communities across Britain in honour of Thomas Mair victim.
The shadow home secretary admits her shock over volume of abuse
Bradford 17-year-old praised Jo Cox murderer Thomas Mair as a 'hero'
Kim Leadbeater revealed how her and Cox suffered from loneliness during their university years.
Labour MP warned against 'knee-jerk isolationism' in report she worked on before she was killed.
The number of reported anti-Semitic incidents was said to have risen by 62% in the UK
Conservative premier urges the UK to be 'more united' after the EU referendum in June.
Jo Cox was the standout choice for our greatest hero of 2016.
Labour MP's widower reflects on the tumultuous events over the past year.
Ricky Wilson and KT Tunstall among singers on cover of Stones' You Can't Always Get What You Want.
White nationalist Joshua Bonehill-Paine given two-tear jail term for anti-Semitic abuse against Labour MP.
The Conservative MP reported the tweet to police and called its sender a 'sad, cowardly troll'.
Interim Ukip leader has stopped 'Friday night pub crawls around Westminster' since 8 November.
Report due to be published on Monday highlights the use of social media to promote hate speech.
Man jailed for life condemned for 'cowardice' murder of Labour MP in Birstall
Killer shouted "Britain first" during attack on MP and gave his name in court as "Death to traitors. Freedom for Britain".
In parts of the UK half of all referrals to 'Prevent' are linked to right-wing fascism.
Murder trial hears how mother-of-two was stabbed 15 times, including to her heart, lungs and liver.
The millions of Brits who are expansive, fair and internationalist will be by us through this dark patch.
Jury shown .22 calibre sawn-off rifle and a dagger reportedly used in the fatal attack.