Facebook would allow the Conservative party to promote its “doctored” video of Keir Starmer as a paid-for advert during the election campaign, the social network has confirmed. But the company has announced a policy aimed at cracking down on pages that conceal their ownership in order to mislead users.

The executive Rebecca Stimson said the public debate that followed the airing of footage of the senior Labour MP in an ITV interview justified the company’s policy of allowing political misinformation on the site.

“You can see, in the UK, what that has meant is that what the Conservatives put in that ad has been the subject of ferocious political debate and discussion, as a result of our policies,” said Stimson, the company’s head of UK public policy.

In the controversial video, posted to Twitter on Tuesday, footage of an interview between Starmer and Piers Morgan was edited in a way that suggested the shadow Brexit secretary was lost for words when asked about the party’s Brexit policy.

The Conservative party maintains that the video was edited not to try to misinform people, but to shorten the clip for social sharing. Morgan himself accused the Conservatives, of having “doctored” the video; a charge denied by the party chairman, James Cleverly.

Facebook’s approach to political advertising suggests the company is unlikely to heed calls from civil society groups to pause political adverts in the run-up to the election.

Stimson said: “Political advertising on Facebook and Instagram is now more transparent than other forms of election campaigning, whether that’s billboards, newspaper ads, direct mail, leaflets or targeted emails.

“We believe it’s important that candidates and politicians can communicate with their constituents and would-be constituents. Online political ads are also important for both new challengers and campaigning groups to get their message out. Our approach is therefore to make political messages on our platforms as transparent as possible, not to remove them altogether.”

On misinformation, Stimson argued: “In general, we believe political speech should be heard and we don’t feel it is right for private companies like us to fact-check or judge the veracity of what politicians and political parties say. In our country it’s always been up to the media and the voters to scrutinise what politicians say and make their own minds up.”

Facebook said a policy aimed at cracking down on pages that conceal their ownership in order to mislead users would bring greater transparency. Its head of security policy, Nathaniel Gleicher, said: “If we find that a page is doing this, we require it to show more information on the page itself about who is behind it, including the organisation’s legal name, and the city it’s set up in.”

The rules appear to finally close a loophole uncovered by the Guardian earlier this year that allowed a lobbying firm owned by the political strategist Lynton Crosby to freely run a widespread propaganda campaign on the social network. CTF Partners, Crosby’s firm, which has worked for Conservative campaigns, owned and ran Facebook pages that purported to be independent news sources on topics ranging from Saudi Arabia’s Crown Prince Mohammed bin Salman to bike lanes in London.

The company then used them to push content created by CTF employees that aimed to promote a particular viewpoint. At times, CTF would build pages that appeared to take opposing sides of the same campaign, in order to more effectively manipulate public sentiment.

Facebook had initially argued that, since the CTF employees were not using fake accounts, the operation did not meet the company’s definition of coordinated inauthentic behaviour, even if users had no way of discovering the lobbying firm’s involvement.

In a similar campaign, operated by Daily Wire, the rightwing US news site ran 14 large Facebook pages anonymously, according to a report by Popular Information. The pages, which disclosed no link to the publisher, funnelled millions of engagements back to Daily Wire content.

Under Facebook’s new policy, however, both Daily Wire and CTF Partners could be required to have their legal names displayed in their pages’ information boxes, possibly preventing the worst abuses.