Police moved in "swiftly" to move travellers who arrived at Fields End Road on Tuesday (February 14) night after several residents reported their arrival.
A council spokesman said: "Police attended Field End Recreation Ground last night and have served a section 61 therefore they have 12 hours to vacate the site, or are escorted off of the grounds."
Police confirmed to getwestlondon that the travellers were moved on from the fields.
A Hillingdon Police officer said: "We and Hillingdon council have a policy of dealing promptly and robustly with unlawful incursions onto public land.
"Those people who moved onto Field End Road fields last night have now been moved on by police and the council are ensuring the final few caravans are also removed from the site."
It is the second time this month police were involved with travellers in the borough after they were called to the former Lidl site in Hayes.
The site has attracted travellers before and in May 2016, around 40 caravans were seen camped up in the car park of the boarded-up swimming pool site.
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