A life-saving treatment for seriously-ill hospital patients with Covid-19 is being used across the UK from June 17, after University of Oxford researchers announced breakthrough results of their trial on June 16.
Dexamethasone - a cheap, widely-available steroid - was shown to reduce deaths among patients on ventilators and on oxygen, reports BBC.
The UK's chief medical officers say it should be used "with immediate effect".
And there are no issues with supplies of the medicine in the UK.
An an urgent letter from the UK's four chief medical officers to clinicians in the NHS, they said dexamethasone had "a clear place in the management of hospitalised patients with Covid-19".
Health Secretary Matt Hancock told the Commons that 240,000 doses of the drug are "in stock and on order".
"It is not by any means a cure but it is the best news we have had," he added.
It comes as the UK government announced a further 184 people have died with coronavirus across all settings in the UK, taking the total to 42,153.
The anti-inflammatory drug was tested as part of the world's biggest trial of existing treatments to see if they could also work against coronavirus.
In the trial, led by a team from Oxford University, about 2,000 hospital patients were given dexamethasone and compared with more than 4,000 who were not.
For patients on ventilators, it cut the risk of death from 40% to 28%. For patients needing oxygen, it cut the risk of death from 25% to 20%.
The researchers said this was equivalent to one life being saved for every eight patients on a ventilator and one life being saved for every 20-25 being treated with oxygen.
'Home a week after taking dexamethasone'
Marium Zumeer, an 18-year-old from Bradford who was given the drug as part of the trial, said it had been "life-saving".
She was admitted to hospital after 10 days of being extremely unwell, and after beginning a course of the drug she was told she would hopefully be home in a week.
"And a week later I did come home," Ms Zumeer said.
On Monday 15 June, 385 people with Covid-19 were on mechanical ventilation in hospitals in the UK with hundreds more likely to be on oxygen support.
They could all be candidates for receiving dexamethasone.
The drug works by dampening down the reaction of the body's immune system to on Covid-19, which can often be more harmful than the virus itself.
Chief investigator Prof Peter Horby said it was "the only drug so far that has been shown to reduce mortality - and it reduces it significantly".
"It's a major breakthrough," he added.
However, it should not be used to treat anyone with coronavirus who is not in hospital. Its use is still being studied in children.
Already used to reduce inflammation in a range of other conditions, including arthritis, asthma and some skin conditions, the cost of the drug would be as little as £5 per patient.
The drug is also widely available around the world.