Doubt has been cast on Dominic Cummings’ claim he warned of the threat of coronavirus “last year” after the discovery of a recent edit on the Downing Street adviser’s blog.

During a press conference on Monday in which he denied he broke UK lockdown rules, Mr Cummings said he had written about the “possible threat of coronaviruses” in 2019.

“For years, I have warned of the dangers of pandemics,” he told reporters.

“Last year I wrote about the possible threat of coronaviruses and the urgent need for planning,” Mr Cummings added.

The PA news agency did find 15 mentions of the term “pandemic” on Mr Cummings’ blog but cached versions of the website show the only mention of the terms “coronavirus” and “SARS” (severe acute respiratory syndrome) were added in April this year.

Site data suggests an edit was made on April 14, the day Mr Cummings returned to work at Downing Street and two days after he visited Barnard Castle with his wife and child.

PA could find no other mention of the terms “coronavirus” or “SARS” on Mr Cummings’ blog or in any other articles available on the internet written by him before 2020.

The edit was made to a post dated March 4 2019 about errors made in laboratories which “could cause a global pandemic”.

The post is predominantly a direct quotation of an article from the Bulletin of the Atomic Scientists posted on February 25 2019.

The article, by Lynn Klotz, a senior science fellow from the Centre for Arms Control and Non-Proliferation, was entitled “Human error in high-biocontainment labs: a likely pandemic threat”.

In the piece, Mr Klotz references a report by the US Government Accountability Office (GAO) about an incident in China where two researchers were exposed to coronavirus samples and transmitted a strain of the disease in 2004.

This is the only time Mr Klotz mentions coronavirus and this section was not included in Mr Cummings’ original post.

In April the section of Mr Klotz’s writing that mentioned coronavirus, a little over 100 words, was added to Mr Cummings’ post – replacing the words “an example”.

Mr Cummings does not mention coronavirus himself but does offer comment on Mr Klotz’s article, saying it shows “how the supposedly most secure bio-labs have serious security problems and clearly present an unacceptable risk of causing a disastrous pandemic”.