Boris Johnson has performed a U-turn after Downing Street announced an internal inquiry into how private text messages between the prime minister and billionaire Sir James Dyson were leaked.
MPs have asked questions of Mr Johnson after it emerged he promised to "fix" an issue over the tax status of Sir James’s employees in a series of messages.
The conversations took place last March in the early stages of the COVID-19 pandemic after the government asked companies, including Dyson, to help supply ventilators.
The prime minister has said he would make "absolutely no apology at all" for "shifting heaven and earth" to secure ventilators for the UK.
But Labour leader Sir Keir Starmer has said the issue demonstrates "sleaze" and "cronyism" within Mr Johnson’s government.
He questioned whether NHS staff or steel workers would get the same treatment if they had the prime minister’s private phone number.
Downing Street has now said the Cabinet Office will investigate how the text exchange between Mr Johnson and Sir James – seen by the BBC – became public.
On Wednesday, Number 10 had initially said there would not be a probe into the issue.
But the prime minister’s official spokesman told a Westminster briefing on Thursday: "I can confirm that, yes, we have instructed the Cabinet Office to look into this.
"The position has changed from yesterday – it was correct at the time yesterday but, as usual, we keep things under review and we have now decided to undertake this internal inquiry.
"As you would expect, we continually look at this and the position we decided today is that we want to make sure we have this internal inquiry into that."
The spokesman confirmed the inquiry will examine the source of leaks of Mr Johnson’s private communication "as related to this issue of Dyson", while he also said Number 10 would publish correspondence between Mr Johnson and Sir James "shortly".
The prime minister told MPs on Wednesday he was "happy to share all the details" of the exchanges.
Meanwhile, the spokesman on Thursday did not deny reports that Cabinet Secretary Simon Case advised Mr Johnson to change his phone number over concerns about the ease with which lobbyists and business leaders were able to contact him.
He said: "We don’t get into details of the advice provided between a cabinet secretary and a prime minister, and so I’m not going to do that in this instance."
Sir James, whose company is based in Singapore, wrote to the Treasury last year seeking assurances that his staff would not have to pay more tax if they came to the UK to help with the ventilators project.
The BBC reported that when he did not receive a response, Sir James raised the issue personally with the prime minister.
He said in a text that his company was ready but "sadly" it seemed like no-one wanted them to proceed.
Mr Johnson messaged back: "I will fix it tomo! We need you. It looks fantastic."
He texted Sir James, again, saying: "[Chancellor] Rishi [Sunak] says it is fixed!! We need you here."
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When Sir James sought further assurance, the prime minister said: "James, I am First Lord of the Treasury and you can take it that we are backing you to do what you need."
In a statement, Sir James said: "When the prime minister rang me to ask Dyson to urgently build ventilators, of course I said yes.
"We were in the midst of a national emergency and I am hugely proud of Dyson’s response – I would do the same again if asked.
"Neither Weybourne nor Dyson received any benefit from the project; indeed commercial projects were delayed, and Dyson voluntarily covered the £20m of development costs.
"Not one penny was claimed from any government, in any jurisdiction, in relation to COVID-19."