A fake advert purporting to have been paid for by scandal-hit Cambridge Analytica has been posted to Facebook.
The ad, now removed but still visible in Facebook's new ad transparency portal, uses the logo of EU referendum campaign group BeLeave, which, in July, was found to have broken electoral law, reports BBC.
It calls for a new immigration policy, saying: "Our current system is broken."
News site Business Insider confirmed to the BBC that it made the ad for a story on Facebook's advertising tools.
Cambridge Analytica closed down operations in May.
"This ad was not created by Cambridge Analytica," a Facebook spokesman said.
"It is fake, violates our policies and has been taken down.
"We believe people on Facebook should know who is behind the political ads they're seeing, which is why we are creating the Ads Library so that you can see who is accountable for any political ad.
"We have tools for anyone to report suspicious activity such as this."
Jim Edwards, editor-in-chief of Business Insider UK said, "We hope our story will push Facebook into making its advertising system more secure and less open to abuse."
The ad was spotted by Guardian and Observer journalist Carole Cadwalladr.
"It just highlights how completely useless Facebook's new transparency rules are," she told the BBC.
"I can't think how they ever thought they were going to work - anybody can write anything in that box."
