The BBC has complained to the Conservatives about a Facebook advert that uses edited footage of its news reporters and presenters.
The BBC says the material has been taken out of context and its lawyers have asked the party to remove the ad.
The 15-second video was first shown on Thursday afternoon and has so far been seen by more than 100,000 users.
The Conservatives said the footage had "not been edited in a manner that misleads or changes the reporting".
Three clips of BBC reporters or presenters - political editor Laura Kuenssberg, News at Ten presenter Huw Edwards and political correspondent Jonathan Blake - speaking in recent broadcasts are used to describe the situation in Parliament.
"Pointless delay to Brexit" and "another Brexit delay" are among the lines of BBC News commentary used.
The clips are edited into a montage of protest footage and video of lively debate in the House of Commons all set to dramatic music.
In a statement, the BBC said: 'We're aware of Conservative Party Facebook adverts using edited BBC content.
"This is a completely unacceptable use of BBC content which distorts our output and which could damage perceptions of our impartiality."
The BBC's lawyers have written to party chairman James Cleverly asking the party to take down the advert.
According to Facebook's Ad Library, the Conservative Party has spent up to £2,200 on the advert so far, which is being targeted at 35 to 54-year-olds in England.
A spokesperson for the Conservative Party said: "This video uses contemporary news footage to remind voters of the deadlock and delay of the last three years caused by a broken Parliament that did everything it could to block Brexit.
"Viewers can judge for themselves but it is clear the footage was not edited in a manner that misleads or changes the reporting."
The party was also criticised earlier this month when it posted a "doctored" video involving Labour's shadow Brexit secretary Keir Starmer, in which he was made to look as if he met a question, posed by ITV's Piers Morgan, with silence when he had answered it straight away.
Mr Cleverly said the video, since taken down, was meant to be "light-hearted". The party later posted an extended version of the interview.
And the Conservatives faced a backlash for rebranding one of their Twitter accounts last week, describing it as a "fact-checking" account during a live TV debate between Boris Johnson and Jeremy Corbyn.
Twitter said the party had misled the public and would take "decisive corrective action" if a similar stunt was attempted again.