@izzythepush,
Counter-protesters seem to outnumber the Brexit 'betrayal' march by five to one. (15,000 joined the Oppose Tommy Robinson rally, compared to 3,000 on the Brexit 'betrayal' march.)
The counter demonstration was organised by Momentum and a coalition of 23 organisations including Stand Up To Racism, anti-fascist and feminist groups.
The "Brexit betrayal" protest is led by Stephen Christopher Yaxley-Lennon ("Tommy Robinson") and Ukip.