Frontline health workers in England are to be spared self-isolation rules in an emergency move to tackle the "pingdemic" that has triggered an NHS staffing crisis.
But after a humiliating U-turn following a public outcry, the PM and chancellor find themselves isolating on what was originally dubbed "Freedom Day" in England after their contact with Mr Javid last Friday.
In a video message posted on Twitter from Chequers, Mr Johnson admitted he and Mr Sunak "did look briefly" at taking part in a pilot scheme that allows people to test daily instead of isolating.
Yet at the same time, despite having been forced into an embarrassing U-turn which took less than three hours, the prime minister also urged the public to remain cautious as restrictions are lifted.
"We’ve got to remember that this virus is sadly still out there," he said. "Cases are rising, we can see the extreme contagiousness of the Delta variant."
Labour leader Sir Keir Starmer, in a letter to Mr Johnson posing a series of questions, asked how he and the chancellor were "magically selected" for the self-isolation trial.
And business leaders and Tory MPs are now piling pressure on the prime minister to end what they claim is a "pingdemic farce" bringing Britain to its knees.
The NHS opt-out is the first major concession from the government to demands for a major overhaul of Test And Trace, which last week saw more than half a million people contacted and forced to isolate.
From today, double-jabbed frontline NHS and social care staff in England who have been told to self-isolate will be permitted to work "in exceptional circumstances and where additional safety measures can be upheld".
The government says this will include staff who have been contacted as a close contact of a case of coronavirus by NHS Test and Trace, or advised to isolate by the NHS COVID-19 app.
And NHS staff members who are contacted will only be able to carry on working after having a negative PCR test and daily negative lateral flow tests.
Announcing the move, Mr Javid, who tested positive on Saturday and is now isolating, said: "As we learn to live with this virus, it’s important that we ensure frontline staff can keep providing the best possible care and support to people up and down the country.
"The government has backed healthcare services at every turn through this global pandemic and these new rules will fortify our collective defences against this awful virus, by allowing fully vaccinated frontline NHS and social care staff to continue to work when needed."
Dr Jenny Harries, chief executive of the UK Health Security Agency, added: "With the number of cases continuing to rise, it is imperative that we do everything we can to manage this virus and support our NHS and social care services under the strain of increased demand and sustained pressure.
"We have provided specific guidance to NHS and social care settings for circumstances where there is a significant risk to health or safety resulting from staff absence or a critical service cannot run.
"This measure only applies to double vaccinated staff, who will only be able to attend work after testing negative on PCR and daily lateral flow tests, and following a risk assessment and the supervision of the health service."
From today in England, social-distancing rules have ended, face masks are no longer mandatory in shops and on public transport, limits on gathering have gone, and the work from home guidance has ended.
Nightclubs, theatres and restaurants can fully reopen, while pubs are no longer restricted to table service only.
While rules have been lifted, government guidelines continue to urge caution with people being urged to meet outside where possible, pubs to continue with table service and employers to encourage a gradual return to the workplace.
Many shops and public transport operators are still asking people to wear face masks while they are a "condition of carriage" on Transport for London.
In Scotland, where restrictions have been eased but not lifted, First Minister Nicola Sturgeon emphasised the need for caution.
The country has dropped to the lowest level of its five-tier system with social-distancing reduced to just one metre, although face coverings remain mandatory in shops and on public transport.
Ms Sturgeon said talk in England of "freedom day" was "not sensible" and that it was important to ease up on restrictions gradually.
It follows a series of rule changes in Wales which came in on Saturday, while in Northern Ireland regulations are expected to ease from 26 July.