PMQs: Sir Keir Starmer presses Boris Johnson on test and trace

Sir Keir Starmer has pressed Boris Johnson on the effectiveness of the NHS test and trace system in England, during Prime Minister's Questions.

The Labour leader said it was a "big problem" that just over 10,000 people with coronavirus had been reached, despite estimates of 33,000 cases.

But Mr Johnson criticised Sir Keir for not supporting government actions.

The PM also dismissed questions about the tracking app for those who come into contact with the virus.

• As it happened: PMQs

• How does contact tracing work?

• Germany has its Covid-19 app, so where's the UK's?

Sir Keir began his questioning by saying Labour supported the government's announcement on Tuesday to ease more lockdown restrictions in England from 4 July.

But he said for it to work safely "we need an effective track, trace and isolate system".

He added: "The prime minister promised a world-beating system would be in place by 1 June.

"I do recognise the hard work that has gone into this, but if two thirds of those with Covid-19 are not being reached and asked to provide contact details, there is a big problem, isn't there?"

Mr Johnson claimed Sir Keir had been "stunned by the success of the test and trace operation", adding: "Contrary to his prognostications of gloom, it has got up and running much faster than doubters expected."

He said 87,000 contacts of those who tested positive for coronavirus had been reached, and called for his counterpart to "pay tribute" to the team working on the system.

But Sir Keir accused the prime minister of "not addressing the question".

The Labour leader said the number of people who weren't reached meant a "big gap" was in the system, adding: "The prime minister risks making the mistakes he made at the beginning of the pandemic - brushing aside challenge, dashing forward and not estimating properly the risk."

Mr Johnson accused Sir Keir of "inadvertently giving a false impression of what test and trace is doing", claiming it is contacting "the vast majority of those who test positive and their own contacts and getting them to isolate".

He called it a "formidable achievement", and said Labour was "yo-yoing back into a position of opposition".

Sir Keir reiterated his support for lockdown easing, but said the PM was "wrong to reject challenge", adding: "65,000 people have lost their lives because of Covid-19. The prime minister should welcome challenge that could save lives rather than complaining about it."

The suggestion that the test and trace system should have reached 33,000 people needs to be treated with caution.

It is the estimate made by the Office for National Statistics based on their official community surveillance programme for the government.

It is based on 10 positive cases from 24,500 people tested. The ONS itself says the low numbers mean any wider extrapolation has to be heavily caveated.

What is more, it will include asymptomatic cases - where people do not display symptoms and do not therefore know they have the virus and so cannot be expected to come forward for testing.

The most recent data for England's test and trace system shows just over 10,000 people who tested positive - three quarters of those passed on to tracers - engaged with the service and provided contacts. Of those contacts, nine in 10 were reached and asked to isolate.

That's not to say there are no weaknesses in the system. There are. But it is hard to determine the extent of the missed infections and whether that is the fault of the system, the public or because of the deviousness of the virus.

How is the tracing scheme going?

The NHS test and trace scheme - which the prime minister claimed would be "world-beating" - was launched on 28 May.

According to figures released on 18 June:

• 14,045 people who tested positive have been referred to the scheme

• Of these, 10,192 (72.6%) provided details of recent contacts

• The contacts amounted to 96,746 people - of these, 87,639 people were reached and asked to self-isolate

The 33,000 figure referenced by Sir Keir Starmer comes from the Office for National Statistics (ONS). It's reached by testing a sample of people and working out what percentage of them are infected and then applying that to the population as a whole.

It's an estimate but not a figure for actual people who have been tested, so tracers would not be able to contact them all.

The Labour leader also questioned the PM about when a mobile phone app to track people who had been in contact with others carrying the virus would be up and running.

He said it was the "only way of tracking unknown contacts", such as people on beaches or in a park, who had been in close contact with one another.

The Labour leader quoted Health Secretary Matt Hancock - who called the app "critical" in May, but later said it was "only ever additional support" - asking the PM, "Which is it?"

Mr Johnson said there was "not a single country in the world that has a functional contract tracing app", but England's test and tracing system was working.

Sir Keir said Germany had a working app with 12 million downloads, before pushing the prime minister on a number of delays to the app and its cost of £12m.

"Other countries are ahead of us," he said. "When are we going to have a working app?"

The PM said his opposite number was "completely wrong" about Germany, and said the government had "always been completely clear that the app was the icing on the cake".

He concluded: "What we do have is a fantastic NHS test and trace operation that is already up and running, that is going to get better and better, and will be indispensable to our future success."