A testing and tracing system considered essential for easing the current coronavirus lockdown will be up and running by June 1, Boris Johnson has announced.

Here are the key dates as the Government moves towards a test, track and trace strategy:

– January 23

Health Secretary Matt Hancock tells the House of Commons that the UK is “ready to respond appropriately” to any cases of coronavirus that emerge.

“The UK is one of the first countries to have developed a world-leading test for the new coronavirus,” he says.

– January 31

After the UK confirms its first two cases, Professor Sharon Peacock, director of the National Infection Service at Public Health England, says the agency is notifying those who came into contact with the two individuals.

– March 11

Faced with increasing calls from MPs for faster and wider testing, Mr Hancock says ministers are “absolutely ramping up the testing capabilities” – but once again does not reveal how many checks are being carried out.

He dismisses testing for everyone, adding: “Testing people who do not have symptoms is not reliable and is counterproductive, so we will not be doing it.”

– March 12

Contact tracing and widespread community testing is abandoned as the Government moves into the “delay” stage of its coronavirus plan.

England’s chief medical officer Professor Chris Whitty tells a Downing Street briefing it is “no longer necessary for us to identify every case”, with only those in hospitals to be formally examined.

– March 16

Dr Tedros Adhanom Ghebreyesus, director general of the World Health Organisation, tells reporters that all countries must “test, test, test” people for the virus.

Later that day, Prof Whitty defends the Government’s position on testing at the daily briefing.

“We do intend to continue to scale up testing,” he says, adding that efforts were already “substantial” – with more than 44,000 tests conducted overall.

– March 25

Professor Neil Ferguson, from the School of Public Health at Imperial College London and a member of the Science Advisory Group for Emergencies (Sage), says widespread testing and contact tracing is required to “help move the country from suppression measures and lockdown into something it can manage long-term”.

– March 26

Deputy chief medical officer Dr Jenny Harries says contact tracing and widespread community testing is “not an appropriate mechanism as we go forward”.

– March 31

Professor Christophe Fraser, from Oxford University’s Big Data Institute, says a contact tracing app is needed to control coronavirus transmission.

NHSX, the unit tasked with driving forward a digital transformation of the UK’s health and social care, says it is “looking at whether app-based solutions might be helpful in tracking and managing coronavirus”.

– April 12

The Health Secretary announces the development of a new NHS app, which will alert other users if they have been in significant contact with someone recently who now has Covid-19 symptoms.

Mr Hancock says developers of the app were working with the world’s leading tech companies and experts in clinical safety and digital ethics “so that we can get this right”.

– April 17

Jeremy Hunt, chairman of the Commons Health and Social Care Committee, calls for “a massive ramp-up – not just in the testing, but also the tracing of everyone who has been in contact with someone who has the virus”.

– April 22

Mr Hancock says the Government will introduce contact tracing at “large scale” as a way of easing lockdown restrictions, as he tells MPs the country had “reached the peak” of the outbreak.

– April 23

Some 18,000 people are now being recruited to help with contact tracing, Mr Hancock tells a Downing Street briefing, expected to be in place by “mid-May”.

Of those, 3,000 are clinicians and public health experts, with training for the remaining 15,000 call handlers.

– April 24

Mr Hancock says it is not quite the case that mass testing and contact tracing need to be in place before easing of restrictions, but said contact tracing worked better when the number of infections is pushed down.

“The smaller the number of new cases, the more effective the test, track and trace system will be,” he said.

– April 28

Matthew Gould, chief executive of NHSX, tells the Commons Science and Technology Committee that people can be “confident” their personal data will not be compromised when using a contact tracing app.

– May 3

The Government announces that the NHSX contact tracing app will be trialled on the Isle of Wight, before it is rolled out more widely.

Transport Secretary Grant Shapps says around 50% to 60% of people will need to use the software for it to be effective as he described it as the “best possible way to help the NHS”.

– May 7

Former TalkTalk chief executive Baroness Dido Harding is appointed to lead the contact tracing programme.

– May 12

Mr Hancock tells Sky News that the contact tracing app trialled on the Isle of Wight is to be rolled out across in England “in mid-May”, adding: “The Isle of Wight project has gone well so far, we’ve learned a lot about how the app operates.

“We’re pleased with progress, and we’re going to bring it in.”

– May 15

Northern Ireland Secretary Brandon Lewis said while “about 15,000” applications have been received, only 1,500 people have currently been hired to be contact tracers.

Downing Street later insists that “significantly more” than the 1,500 had been recruited, but was unable to say how many.

– May 18

Mr Hancock tells MPs that 21,000 tracers are now in place to manually track people who have come into contact with infected individuals – exceeding the target of 18,000.

Earlier, Downing Street told reporters the contact tracing app will be launched across the country in the “coming weeks”.

– May 20

Mr Johnson tells MPs that a testing and tracing system will be up and running by June 1, but the rollout of the contact tracing app will come later.