He has also hinted he may have documentary evidence to back his assertions which he could potentially produce.
In a week when whatever he chooses to say is likely to become front page news, we took a look at what he might say and his background in British politics.
When is Dominic Cummings appearing before MPs?
Mr Cummings will give evidence to the joint inquiry of the health and science and technology committees into lessons learned from the pandemic on Wednesday at 9.30am, when he will talk about government decision-making.
The session for the inquiry, called Coronavirus: Lessons Learnt, will be televised. You will also be able to follow what he says right here on the Standard website.
What is Cummings likely to say to the committee?
Based on what he has been posting on Twitter, it seems likely he will be asked about his claim the government’s original response to the coronavirus outbreak was to pursue a strategy of “herd immunity”.
In a series of explosive tweets, the Prime Minister’s former top adviser said the policy – to build up resistance in the population by allowing some spread of the disease – was only dropped in March last year after a warning it would lead to a “catastrophe”.
He said herd immunity “was officially seen as UNAVOIDABLE” at one point and was “seen as easier to manage & less of a catastrophe”.
The committees have said Cummings will “face questions on decisions taken, during his time working in Government, to deal with the threat of Covid-19”.
In his original tweets, Mr Cummings claimed there may have been no need for any lockdowns if the country had had the “right preparations and competent people in charge”.
He is known to have strongly made the case for a second lockdown in the autumn which the Prime Minister has been accused of being too slow in ordering.
Cummings has claimed to have a dossier of evidence against the government and Boris Johnson, and asked his Twitter followers what he should do with it, with many voting in favour of him sharing it on his blog page.
The hearing is expected to focus on:
* Decision-making in the early months of the pandemic.
* The level of scientific evidence available to the Government.
* Its border policy.
* The effectiveness of its public health messaging and communications.
* The timing of lockdowns and other restrictions, procurement processes.
* Decisions about community testing and contact tracing.
Who is Dominic Cummings?
The arch-Brexiteer and once right-hand man of the Prime Minister Boris Johnson shot to national prominence and notoriety following his ill-fated trip to Barnard Castle during lockdown. He was already well known as the architect of the successful Vote Leave campaign during the 2016 EU referendum.
The excursion to Barnard Castle sparked a furore at a time we were all being told not to travel beyond our local area.
49-year-old Mr Cummings has been an influential figure in British politics for years.
Despite positioning himself as a populist campaigner, he was privately educated at Durham School before gaining first-class degree in modern history at Oxford University.
He spent some time in Russia, where he was supposedly involved with a doomed attempt to launch an airline, although details of his activities in the country remain sketchy and unclear.
Cummings is married to Mary Wakefield, 45, a commissioning editor at The Spectator. They have a son, Alexander Cedd - named after the early English saint - who was born in 2016.
What is Cummings’ political history?
His first role in mainstream politics was as a chief strategy adviser to the then Conservative leader Iain Duncan Smith.
In 2004, he got his first taste for referenda as he took a prominent role in campaigning against an elected regional assembly in his native north-east.
It was this campaign - which remarkably convinced the electorate to vote for the consolidation of political power in Westminster - that was used as a dry run for the EU referendum many years later.
During the campaign, Mr Cummings and several associates who would go on to work alongside him as part of Vote Leave in 2016 used eye-catching media-friendly stunts such as burning wheelbarrows of fake bank notes.
It was also during the North East Says No campaign that Mr Cummings first latched on to the idea of telling the public their money would be better off going towards the NHS, although at this point it was not plastered on the side of a bus.
He went on to work as an adviser the then education secretary Michael Gove before re-emerging years later as the head of the Vote Leave campaign.
Although ultimately successful in winning the Brexit referendum, it was later fined £61,000 and referred to the police for breaking electoral law.
What happened when he got into No 10?
After winning the Brexit referendum and once key ally Boris Johnson finally fulfilled his long-held ambition of becoming Prime Minister, Mr Cummings began working as a top adviser inside No 10 in July 2019.
His return to the spotlight was not without its controversy.
In August 2019, Cummings sacked Treasury special adviser Sonia Khan, without the permission or knowledge of Chancellor of the Exchequer Sajid Javid, and asked an armed officer to escort her off the premises.
In November 2019, a whistleblower raised questions about his activities during his time in Russia and the Sunday Times reported that Whitehall was keeping certain government business from him.
He also led a drive to recruit data scientists and forecasters to Downing Street. It resulted in the appointment of Andrew Sabisky, who later resigned following complaints about his views on race, intelligence and eugenics.
Will O'Shea, a data specialist, was fired in July 2020 after calling for police to shoot Black Lives Matter protesters.
Why did Cummings fall out with Boris Johnson anyway?
Boris Johnson reportedly axed Cummings in November 2020 after he reportedly branded his fiancée Carrie Symonds “Princess Nut Nuts”.
It supposedly resulted in the Prime Minister ordering Cummings along with No 10’s director of communications Lee Cain to leave Downing Street.
It followed a number of leaks from No 10 during the Covid pandemic, with journalists being briefed on lockdown measures and restrictions ahead of any official announcement.
He left No 10 via the front exit where the gathered media are positioned while carrying a box of his belongings in a seemingly carefully choreographed exit.
This has since led to the PM and Cummings briefing against each other in the media as to who the so-called “chatty rat” leaker is, with an official inquiry admitting it is unlikely to resolve the matter.