Caravans and other vehicles have been parked on the Lancaster City Council owned car park behind The Grand Theatre in St Leonard’s Gate since Thursday, October 24.
A council spokesman said: “They arrived on Thursday evening and were served notice to quit on Friday, giving them until Saturday morning to leave.
“They did not comply with the notice and as a result our legal team will be seeking a court order today to regain possession of the land.
“The cleansing team are visiting the site regularly to clear up any rubbish.”