The X owner claimed "massive uncontrolled migration" was leading to the "destruction of Britain" and criticised the government's failure to protect citizens.
Musk warned the crowd that "violence is coming" and urged them to "fight back or you die", appealing to "British common sense".
The rally, attended by an estimated 110,000 people, was attended by Ben Habib, leader of Advance UK, a political party recently joined by Robinson.