The leader of the English Defence League, Tommy Robinson, was believed to be among 53 members of the EDL arrested yesterday.
EDL sources said they were planning a surprise demo in Whitechapel, east London.
Last week Tommy Robinson, 29, tweeted: “Its death, prison or glory. We shall not submit #nosurrender”
Dozens of police in riot vans swooped on vehicles carrying EDL members on the M1 near Luton, Beds, in what officers called a “pre-event investigation.”
The group had been planning a protest next Saturday in Walthamstow, north-east London. A similar protest in the area in September ended in violence with 20 arrests.