The area had to be closed to traffic as the group gathered outside Downing Street on Saturday afternoon.
The demonstration came after the founder of the English Defence League – real name Stephen Yaxley-Lennon – was detained by officers while streaming a Facebook live video outside a grooming trial in the West Yorkshire city on Friday morning.
He currently remains in custody.
Furious followers, mainly white men, can be heard in videos of the demonstration singing Robinson’s name. Footage shows one man being lifted atop of gates before turning to the crowd and pumping his fist, while others chant “shame on you” to authorities.
Members of the crowd can be seen holding aloft “#FreeTommy” signs or waving flags, including the St George’s Cross, the Union Jack and the Ukip logo.
At least one protester was seen carrying a 'White Lives Matter' placard. Footage of the demonstration showed some of those present involved in minor scuffles with police.
The protest later moved to Parliament Square but the Met Police said there had been no arrests.
Online, meanwhile, some 70,000 people have signed a petition calling for Mr Robinson to be freed.
Robinson co-founded the English Defence League (EDL) in 2009 and has been arrested numerous times during demonstrations and at fights between football fans. He was jailed for mortgage fraud in 2014.
After claiming to have made friends with Muslim prisoners during his time in prison, he tried to launch a British branch of the German anti-Islam group Pegida in 2015.
In recent times he has been linked with members of the ethno-nationalist Generation Identity movement, whose leaders have been prevented from entering the UK.