Phillipson's remarks came after Reform UK suspended councillor James Regan for making racist comments during protests outside the Bell Hotel in Epping.
Reform UK's deputy leader, Richard Tice, dismissed Phillipson's accusations as "ridiculous" and "outrageous", denying the party encourages unlawful behaviour.
The political exchanges occurred amidst ongoing protests across the UK concerning migrant hotels, including an incident in West Drayton where five people were arrested.
The government recently won a court challenge allowing asylum seekers to continue being housed at the Bell Hotel in Epping, which has been a site of demonstrations.