Travellers have been given 48 hours to leave after setting up camp in a park.
Two caravans arrived in the car park of Chandos Recreation Ground, in Camrose Avenue, Edgware, on Saturday evening.
Alarmed neighbours alerted Harrow Borough Council to the disturbance and officers today issued an eviction notice to the travellers to leave within 48 hours.
Council leader Cllr Susan Hall said: “This has nothing to do with lifestyle choice or background; it is simply a case of where people have permission to stay.
“Planning laws apply to everyone and it is not fair on residents that any group is allowed to flout them.”
Last year around police moved on an encampment of 20 caravans on the site of the Kodak Sports Ground in Harrow View.