Keir Starmer grilled Boris Johnson’s stand-in Dominic Raab on the huge gap between testing capacity and the number of actual tests performed at his first PMQs as Labour leader.
Mr Starmer said the Government is not making full use of its testing capacity to see if people have Covid-19 - and had been “very slow” to respond.
He added: "The Health Secretary made a very important commitment to 100,000 tests a day by the end of April, but yesterday the figure for actual tests was 18,000 a day and that was down from Monday, which was 19,000 tests a day.
"We're way behind the curve and the end of the month is a week tomorrow. So, what does the First Secretary expect to happen in the next eight days to get us from 18,000 tests a day to 100,000 tests a day?"
Responding, Mr Raab appeared to indicate the government’s target was to have capacity for 100,000 tests a day, which it is not.
Responding, Mr Raab said testing capacity was up to 40,000 a day and will increase "exponentially" by the end of the month.
He added: "I do have to just correct him. Our capacity for tests is now at 40,000 per day, so I think that is an incredibly important milestone.
"Of course, he is right to say that in the final week that will require a big increase.
"But, of course, with a project like this, it does require an exponential increase in the final days and the final week of the programme."
Announcing the target on April 2, Health Secretary Matt Hancock said it would be on tests performed, not capacity.
He said: “I’m now setting the goal of 100,000 tests per day by the end of this month. That is the goal and I’m determined we’ll get there.”
Mr Starmer returned fire, pointing out the target was for completed tests rather than capacity, and saying the Government's testing plan for NHS workers had an "obvious problem".
He said: "Last week the Health Secretary said that every care worker who needed a test would get one. But the reality on the ground is very different, and there are very few tests indeed.
"The position is this - if a care worker has symptoms of coronavirus or a family member has symptoms, he or she has to self-isolate, quite rightly.
"To get a necessary test, they are then instructed to travel to a testing centre, which is often very many miles away."
He added: "Now there's an obvious problem with that system. Not all care workers will have access to a car, because they've got symptoms or family members have got symptoms they obviously can't use public transport, so it is little wonder we're seeing these pictures of half-empty testing centres.
"What reassurance can the First Secretary give to care workers on the front line that things will approve for them and fast?"
Later Health Secretary Matt Hancock told MPs : "I've set the goal of 100,000 tests a day by the end of this month and I'm delighted to say that the expansion of capacity is ahead of plans, even though demand has, thus far, been lower than expected."
