The government's new cost of living tsar called for Boris Johnson to quit over Partygate and said the PM is not "particularly blessed" with "intelligence or integrity".
In a series of tweets which emerged today, David Buttress, founder and former chief executive of Just Eat, said the PM had "to go" over rule-breaking parties in Downing Street and that voting Conservative in Wales was "self harm".
He has also accused the government of "prejudice, lack of common decency and humanity" over its treatment of asylum seekers crossing the Channel.
The multi-millionaire venture capitalist was appointed by the PM to “work with the private sector to develop new business-led initiatives to help people struggling with the squeeze on living standards”.
A Labour source quipped: "We don't often welcome Boris Johnson's hires but this guy appears to have great judgement."
In a tweet sent in January, when the PM was under fire over Partygate, the businessman said: "Why is it that the worse people often rise to the highest office and stay there!?
"For me, it isn't important what job you do or your title, but it is vitally important why you do the job and what you achieve.
"Boris has to go, he just has to. You can't survive judgment like this."
On April 26, of this year, just ahead of the local elections, he fumed at the "cost of decades of Westminster Conservative neglect of Wales" and a "total absence of investment strategy for the country", claiming the government had "destroyed Welsh communities and the concept of society in England".
And in March, as part of a tweet about leadership, he said: "A person's character is formed from many places and experiences. ‘Surprisingly’, Eton, Oxford, into politics and then Prime Minister doesn’t necessarily capture the best gene pool."
In separate tweets, he said: "Never confuse an expensive education with intelligence or integrity. I don't think Boris is particularly blessed with either, imagine if he had not had the many privileges he has experienced.
"Does anyone believe he would be PM on merit? Not a chance mate. 19 PMs from Eton."
Mr Buttress has also been a passionate advocate of Welsh independence – something the Government opposes – complaining “no party in the last hundred years has done more damage to Wales than the Conservatives”.
In one speech in January 2020, he declared: “Time is up on Westminster for me. Let them have the kind of powers and government that they want.
“Let them fill it with Boris Johnsons and right wing extremism – have what they like – but that is not the Wales I know. It is not a government I can recognise.”
And, as the government comes under pressure over its new immigration policy to deport asylum seekers to Rwanda, it emerged that Mr Buttress tweeted in December he fired off an an angry tweet about the "prejudice, lack of common decency and humanity that this government is showing the refugees crossing the channel".
He added: "I believe we need to show these poor people, trying to find a safe place to live their lives that they are very welcome here."
The PM formally announced Mr Buttresses appointment on Tuesday, trumpeting the news online.
He tweeted: "We’re appointing a Cost of Living business tsar, @davidjusteat, former CEO of @JustEatUK. In partnership with businesses, he will develop and promote initiatives that help households and families with rising costs."
Today, the Prime Minister's spokesman said Mr Buttress' tweets were "not relevant" to his role, adding: “We want to get people with the right experience into important roles such as these.
“I think anyone who looks at Mr Buttress’ CV can see that he’s well-qualified to advise the Government in this specific area.”
The spokesman said the tweets “are not relevant to the role he is doing where is working with the private sector to identify, develop and promote new and existing business-led initiatives to support people with the rising global cost of living”.
The spokesman admitted he did not know if the Prime Minister was “aware of every single comment” published but “relevant due diligence had been done”.
