It is understood Kent police are looking to prosecute for public nuisance and wilfully obstructing a highway. Public nuisance is infrequently used as a criminal prosecution but, as a common law offence, can be tried in the crown court with sentences of a year or more in the past.

Police are also investigating conspiracy to cause danger to road users, an offence that could be used where there is evidence that protesters stepped into the path of oncoming traffic, as happened last week.

Section 22 of the Road Traffic Act of 1988 makes it illegal to “cause anything to be on or over a road… in such circumstances” that it would be “dangerous”. It carries a maximum penalty of seven years in jail.

A National Police Chiefs’ Council spokesman said: “Hundreds of arrests have already been made by police in areas that have been affected and officers will continue to act swiftly to stop protesters from causing major disruption to UK motorways and risking their safety and the safety of others.