Observer journalist Carole Cadwalladr has vowed to fight a “ridiculous” claim for defamation made against her by Leave.EU campaign donor Arron Banks.

Prominent Brexiteer Banks has objected to Cadwalladr claiming in two recent speeches that he was offered money by the Russian Government and that he has lied about his relationship with the regime.

Cadwalladr has spent the past two years investigating the Leave.EU co-founder as part of her work exposing the harvesting of millions of Facebook users’ data by the now-defunct Cambridge Analytica and the wider impact of technology misuse on democracy, including in the 2016 EU referendum.

A letter sent today by lawyers Kingsley Napley on behalf of Banks warned Cadwalladr that defamation proceedings would be issued against her seeking damages and an injunction unless she gave a “prompt and satisfactory” response.

Banks complained about a speech made by Cadwalladr in Westminster on 4 June in which she said: “We know that the Russian Government offered money to Arron Banks.”

Banks has denied receiving money from Russia.

The speech, made at an event called The Convention: Never Again at which Cadwalladr was keynote speaker, is now available to watch online and has been viewed more than 1,800 times.

Banks also objected to Cadwalladr’s Ted Talk called “Facebook’s role in Brexit and the threat to democracy” from April this year, which has been viewed more than 2m times.

In the talk, referring to allegations that Leave.EU had broken electoral funding laws, she made further allegations involving Banks and the Russian government.

Cadwalladr told Press Gazette that after many legal threats made by Banks towards The Guardian about her work, this was the first aimed at her personally.

“There’s no merit to their claim,” she said. “This has all been published by Parliament.

“This is all evidence that we published in the Guardian that the New York Times published, that the Sunday Times published, and it was also included in the Parliamentary report. It’s in Hansard.

“So it’s ridiculous to go after me and I am very happy to contest this and I am certainly not going to be withdrawing my claims because it is based on public evidence.

“It’s just more bullying and intimidation.”

Banks has previously described Cadwalladr as a “sad cat lady” in a tweet, language which was mimicked by BBC Politics Live host Andrew Neil in November when he called her a “mad cat woman”.

The post, which also dubbed Cadwalladr “Karol Kodswallop”, was deleted soon afterwards as the BBC called it “inappropriate”.

Sharing the legal letter on Twitter, Cadwalladr said today: “Russian-connected businessman under investigation by National Crime Agency threatens journalist who helped expose him.”

Banks and Leave.EU face a probe by the National Crime Agency after the Electoral Commission told the unit it suspected the businessman was “not the true source” of £8m of loans split between the Leave.EU campaign and Better for the Country Ltd.

The letter sent to Cadwalladr today stated that both statements being complained about “would have the tendency to substantially adversely affect Mr Banks’ reputation”.

“The suggestion within the Convention talk that the Russian Government would offer him money clearly implies that there was a belief that he might be ‘bought’ by a foreign power that is adverse to the United Kingdom in certain fundamental respects,” the letter said.

“The outright statement within the Ted Talk that Mr Banks has lied about his covert relationship with that same government clearly implies not only dishonesty but that there is something further to hide by way of his dealings with that foreign power.”

Documents seen by the Observer last year suggested Banks had three meetings with Russian embassy officials in the run-up to the Brexit referendum. He had previously disclosed only one.

He subsequently denied that Russian officials had sought to influence the Leave.EU campaign.

Picture: Press Gazette