Arron Banks, the insurance businessman who co-founded the pro-Brexit Leave.EU campaign, has dropped two elements of his libel claim against the investigative journalist Carole Cadwalladr.

His decision means the action will still proceed but only over statements made in a public Ted Talk last year and in one related tweet. Her full defence is due to be delivered to the court this month.

Cadwalladr has won a series of prestigious journalism prizes for her work published in the Guardian and Observer exposing the Cambridge Analytica data-harvesting scandal and spending by pro-Brexit campaigners in the EU referendum.

In a tweet on Thursday, Cadwalladr said: “Banks has dropped claim against 1 talk & tweet. BUT he’s carrying on with TED talk & tweet 2. Sigh. I’m SO VERY grateful to everyone who gave to crowdfunder. But I’ve ringfenced that in case of costs. And am launching this to help pay current legal fees.”

In a preliminary ruling last month on the meaning of her words, Mr Justice Saini cautioned against an overly legalistic interpretation and emphasised that the ordinary reader or listener would not minutely analyse possible interpretations of words like a libel lawyer.

Saini concluded that the Ted Talk and the related tweet meant that: “On more than one occasion Mr Banks told untruths about a secret relationship he had with the Russian government in relation to acceptance of foreign funding of electoral campaigns in breach of the law on such funding.” Banks alleges that the meaning is defamatory.

Cadwalladr, who is being sued personally by Banks, is supporting her defence through the crowdfunding website CrowdJustice.

Tamsin Allen, at the law firm Bindmans, who represents Cadwalladr, said: “He appears to have recognised after the judgment that there was no merit in pursuing those [other] parts of the claim. The remaining part will be very strongly defended.”

Banks’s solicitors, Kingsley Napley, were approached for comment.

In a statement last year, the Guardian’s editor-in-chief, Katharine Viner, and the Observer editor, Paul Webster, said: “Carole’s brave reporting has made waves around the world, and given the public much more insight into the secretive ways some powerful people and organisations have sought to influence our democracies.

“This case is a very worrying example of a wealthy person singling out an individual journalist and using the law to stifle legitimate debate and silence public interest journalism.”

A coalition of free press organisations, including Reporters Without Borders and Index on Censorship, has called on Banks to withdraw the legal action.