A range of groups and figures from the British far-right and Christian nationalism are expected to attend the event, which will call for a General Election.
Sir Keir, who met senior police figures and officers involved in Saturday’s operation, said: “We are in a fight for the soul of this country, and the Unite the Kingdom march this weekend is a stark reminder of exactly what we are up against. Its organisers are peddling hatred and division, plain and simple.
“We will block those coming into the UK who seek to incite hatred and violence. For anyone who sets out to wreak havoc on our streets, to intimidate or threaten anyone, you can expect to face the full force of the law.”