Health Secretary Matt Hancock has revealed he lost half a stone while suffering from coronavirus.
The cabinet minister tested positive for COVID-19 last week and entered self-isolation.
After a seven-day period, he left self-isolation on Thursday and announced a five-point action plan to achieve a “significant” increase in coronavirus testing.
It followed criticism of the government’s approach to testing and the UK’s low level of testing in comparison to countries such as Germany and South Korea.
Speaking to Sky News on Friday, Mr Hancock said he had been working “every day” with Prime Minister Boris Johnson, who also contracted coronavirus, during his self-isolation.
Describing the effects of the disease, the health secretary said: “It is rough, especially when you are on the downhill part of it – it’s very worrying because we’ve all seen how serious it can get.
“I had a couple of days when it was really very unpleasant and I’ve lost about half a stone.
“But, thankfully, I’ve recovered and I’m now feeling fine and it’s very good to be back at work.
“I’ve talked to the prime minister all the way through this, he’s working very hard as much as he can from home, obviously, in Downing Street.
“I’ve worked with him every day all the way through and he’s doing what’s needed in taking the decisions and we all wish him a very speedy recovery.”
Mr Hancock’s plan to increase testing to 100,000 tests per day in England by the end of this month includes the use of universities and private businesses to establish more swab testing.
He admitted the target to “ramp up” the amount of testing was “a big task, a big ask”, with the current level of testing around 10,000 tests per day.
But the health secretary pointed to the building of a new make-shift NHS hospital in east London as an example of the government being able to achieve action in the face of the coronavirus crisis.
“We’re opening the NHS Nightingale today, we managed to build that in nine days,” he said.
“On ventilators we asked companies that haven’t ever made a ventilator before to step up to the plate and they’re delivering ventilators.
“And now we need to do the same on testing.”
Among criticism of the current level of testing in the UK have been concerns about the level of testing of NHS frontline staff.
The Royal College of Physicians has previously warned around a quarter of NHS doctors are off work due to sickness or because they are in isolation.
But Mr Hancock said that figure was “wrong” and 5.7% of doctors and just under 8% of all NHS staff are currently off work.
He added the government “want to get that number down”, which is why it is increasing the level of testing of NHS staff.
As of Thursday, 5,000 frontline staff had been tested, Mr Hancock said, with the families of hospital workers also having started to be tested as well.
Explaining the importance of testing in order for the UK to exit the lockdown measures put in place by the government, Mr Hancock added: “The first step is to get the rate of infection down so that that isn’t increasing.
“It takes some time after the lockdown is put in place to get that rate of infection, the rate of transmission down.
“Then we need to make sure that we have the testing in place and the tracking so that if we release any of the measures, we don’t simply then have the infection spread again in the way that it was starting to spread when we brought the measures into place.”