The House of Commons Liaison Committee brings together the chairs of the 36 separate House of Commons committees. It is, by custom since 2002, the only committee with the authority to summon the Prime Minister, providing a forum in which the head of government can be subjected to intense scrutiny.

The Committee usually convenes biannually to question the Prime Minister and other relevant figures, but it had yet to question Boris Johnson since he took over as Prime Minister in July 2019. Just last week, the government successfully appointed a new Chairman, Sir Bernard Jenkin, a prominent and cerebral Tory backbencher, to replace the incumbent Hillary Benn.

But if Boris Johnson was hoping for an easy ride, he was mistaken. The members of the Committee wasted no time in putting the Prime Minister and his government’s policies under the spotlight.

The Chair of the Committee, Sir Bernard Jenkin, opened the proceedings by asking the Prime Minister whether his recent defence of his chief adviser, Dominic Cummings, “has undermined the moral authority of the government with the public at a time when public confidence in the government is so important.”

The Prime Minister responded: “I must say that I feel that on my adviser…I’ve commented on it, I think people know my views, I really don’t propose to add to it.” He urged politicians to “unite our message” to focus on helping the country get through the epidemic and out of the lockdown.

He confirmed that he would not be calling on the Cabinet Secretary to lead a formal investigation to inspect the matter further.

In response to later questions, the Prime Minister expressed frustration that: “A lot of the allegations that were made about” Dominic Cummings “were simply not correct. And I don’t think that point has been sufficiently acknowledged.”

But the issue would not go away. The Prime Minister’s remarks didn’t prevent MPs from all parties, including Conservative MP Simon Hoare, following up with some tough questions alongside Labour’s Meg Hillier and Yvette Cooper.

In one particularly lively exchange, Cooper drew attention to in the government’s own advice to parents who are sick with Covid-19 and seeking childcare. She accused the Prime Minister of putting “political concerns ahead of clear public health messages to parents who have coronavirus”, and his chief adviser before the national interest.

The Prime Minister fought back, calling for MPs to “lay aside party political point scoring and to put the national interest first”.

A series of questions were put to the Prime Minister on the “test, track and trace” programme which is due to be unveiled by the government tomorrow. According to Johnson, this will employ an army of 25,000 contact tracers, the UK’s testing capacity, and a new NHSX tracing app to move towards a “world-beating” system to contain the virus and bring Britain out of lockdown.

Greg Clark, Conservative MP and the Chair of the Science and Technology Select Committee, called on the Prime Minister to revise the UK’s 2 metre social distancing rule down to 1 metre. This is a measure which Clark says could have “a massive impact on whether many workplaces can open” over the coming weeks.

When faced with questions about the government’s contact tracing strategy, Boris Johnson clarified that, from tomorrow, those in contact with those who have Covid-19, but who test negative, will still be required to self-isolate for fourteen days.

This will be an obligatory requirement rather than a voluntary preference, the Prime Minister said, and those breaking the quarantine rules could be subject to “financial sanctions”.

Addressing concerns that this would be a particularly burdensome policy for many, the Prime Minister said: “That captivity for a tiny minority for a short time will allow us gradually to release 66 million people from the situation”.

Yet some concerns remain about the extent to which the government’s new programme will be fully fit and ready for its grand opening tomorrow.

The Chairman of the Health Select Committee, Jeremy Hunt, queried the government’s turnaround time for tests, urging that there is still too long a period of time between individuals getting tested for coronavirus and the point at which they get their result back.

Hunt argued that the current average in the UK, about 48 hours, needs to be cut down to 24 hours in order to provide a service on a par with countries such as South Korea and Taiwan, both of which have been praised for their highly effective testing and tracing programmes.

“We are reducing the time delay on getting the test results back.” Getting down to 24 hours is the aim, but the Prime Minister refused to provide a deadline for the target.

“What we will have tomorrow will be valuable, it will be useful, it will be a very important tool in our fight against coronavirus, but getting steadily better to become a truly world-beating test and trace operation in the course of the next days as we go through June. This has gone from a complete standing start to a huge operation.”

“The brutal reality”, the Prime Minister said, “is that this country did not learn the lessons of SARS or MERS and we didn’t have a test operation ready to go on the scale that we needed. We now have that.”