The BBC has demanded the Conservatives take down a “completely unacceptable” Facebook advert using clips from its journalists, claiming it could “damage perceptions of our impartiality”.

But the party has refused, defending its use of contemporary news footage and insisting “viewers can judge for themselves”.

The 15-second advert uses video and audio clips of BBC journalists reporting on defeats in the House of Commons that have further delayed Brexit since Boris Johnson became Prime Minister.