Boris Johnson has vowed to increase the UK’s Covid-19 testing capacity to 500,000 tests per day by the end of October in a bid to keep any potential second wave this winter under control.

The Prime Minister warned that the rise in the number of people with coronavirus-type symptoms due to seasonal illnesses could make the job of tracking the virus harder in colder months.

Speaking at a press briefing at Downing Street, Mr Johnson said testing capacity currently stands at 200,000 per day.

The PM said: “As we approach winter we will need to go further, not least because many more people will show Covid-like symptoms as a result of seasonal illnesses and therefore require a test.

“So we will further increase testing capacity to at least 500,000 antigen tests a day and 3.5 million antigen tests a week by the end of October.”

Mr Johnson said as the Test and Trace system improves, it will give health officials the ability to detect outbreaks “in real time”.

“The closer we can get to pretty much instantaneous detection of outbreaks, the better we will become at preventing a more general outbreak,” he said.

Mr Johnson confirmed the extra £3 billion in funding for the NHS to prepare for a possible second wave of infections, warning the disease could become “more virulent” in winter.

“We’re making sure we’re ready for winter and planning for the worst,” he said, but added: “Even as we plan for the worst I strongly believe we should hope for the best.”

Dido Harding, head of the NHS Track and Trace service, said the system had improved dramatically over the six weeks since it was introduced.

Speaking alongside Mr Johnson, she said almost two million people have now been tested, with 34,000 testing positive and 180,000 of these patients’ contacts being traced.

Ms Harding said Britons could now be confident that they would receive their test results.

“Every week NHS Test and Trace gets better and we are working hard to keep improving,” she said.

But she added there was “a lot more to do”, promising that an NHS Test and Trace app would soon be launched, along with backwards-contact tracing to find the source of an outbreak.

She also warned it was still too early to roll out antibody testing, which was previously hailed as a “game changer” by the Prime Minister.

“At this stage the science isn’t clear enough yet to tell us whether or not the presence of antibodies and the level of antibodies in your blood gives you immunity,” Ms Harding said.

“Everyone wants to believe we will find that silver bullet in the science that means we know we’re going to be safe.”

She added: “There are no plans immediately to extend that antibody testing, unless the science gives us that answer we’re searching for.”