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Boris Johnson’s pledge to have a “world beating” coronavirus test-and-trace system in place by next week has been thrown into doubt after the NHS chief in charge of the plan said key elements would not be fully operational until the end of June.

Dido Harding, executive chair of NHS Test and Trace, told MPs on a Zoom call on Thursday it would be several weeks before local action plans were ready.

Local enforcement is seen as essential for proper working of the scheme but critics have warned councils are not yet fully prepared for ‘micro-lockdowns’ if there are fresh oubreaks of the virus 

Her remarks came amid growing concern that the system was launched prematurely today in a bid to meet the prime minister’s deadline of June 1.

Health secretary Matt Hancock laughed off suggestions that the scheme had been fast-tracked to distract attention from the ongoing row over the breach of lockdown rules by the PM’s aide Dominic Cummings.

The PM had promised to get the system up and running, complete with a capacity for 200,000 tests a day, by the start of June.

But Johnson himself conceded to MPs on Wednesday that the system would need to improve over coming weeks before it could properly be called “world beating”.

It currently lacks the ability to deliver all test results within 24 hours, seen by many as crucial for an effective scheme.

Labour’s Ben Bradshaw and Lib Dem Daisy Cooper both tweeted after a call for MPs with Harding.

Bradshaw wrote: “Dido Harding just told me on an MPs’ conference call that Test, Trace & Isolate won’t be fully operational at local level till the end of June. Not sure where that leaves Johnson’s promise of a fully operational ‘world beating’ system by Monday.”

Cooper added: “Dido Harding just told me that the #NHSX app described by PM a week ago as ‘world-beating’ is in fact just a ‘cherry on top’ of the tracing system: which itself won’t be fully operational until end June… Four weeks after lockdown restrictions ease. This is a high risk strategy.”

The boss of NHS chief executives this week expressed doubt that the system could possibly work properly as local public health officials – crucial to the working of the plan – had been given insufficient notice, information or cash.

Bradshaw told HuffPost UK that he wasn’t surprised by Harding’s admission because he had already been told by his local officials in Devon – one of 11 chosen to pilot the system – that it would not be ready in his area for some time.

“Given everyone knows this can only work if tracing follow up and enforcement is working at local level it’s clearly not going to be fully operational as Boris Johnson promised at PMQs last week,” the MP said.

“I’m not quite sure why the government announced it when it’s clearly not ready. One can’t help wondering whether it’s all part of their attempt to ‘move on’ from Dominic Cummings.”

Hancock admitted on Thursday that the NHS app, seen by some as key to the speedy working of the system, would not be ready for “a couple of weeks”.

The national system went live at 9am, but it remains unclear how it will be enforced at local level.

One government source said that there was a difference between the national tracing scheme and local action plans being worked up to accompany it.

“This idea we’ve rush in Test And Trace ahead of plan is simply wrong. it was planned to go live today from last week, well before the DC [Dominic Cummings] stuff.”

In evidence to the Commons Liaison Committee on Wednesday, Johnson came close to admitting that the system was not fully ready.

“We must be absolutely clear about this, I’m not going to pretend to you and the committee that this…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 it will be 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 government has said councils will be central to supporting the new service across England and they will be helped with a new £300 million funding package.

Each of the 11 council pilot areas will be expected to develop outbreak control plans for schools, workplaces and other areas and some experts say the entire system cannot work properly without them.

On Wednesday NHS Providers chief executive Chris Hopson said he was pleased the Government had watered down claims it had a “world class” test and trace system ready to start from June 1, “because we clearly don’t”.

“There will be a group of contact tracers who will be ready (on Thursday) morning but there are still very key bits of test and trace that still need to be built,” he told BBC’s Newsnight.

Under the new NHS Test and Trace system, individuals will be one phone call away from being told to self-isolate for up to a fortnight if a new army of 25,000 tracers identify them as having had “close contact” with others who have tested positive for the virus.

The programme defines “close contact” as being within two metres of someone for more than 15 minutes without any protection such as a plastic screen or protective equipment.

NHS contact tracers or local public health teams will ask anyone who tests positive for Covid-19 to share details of the people they have been in close contact with and places they have visited.

The “detective” team then emails or texts those close contacts, telling them they must stay home for 14 days even if they have no symptoms, to avoid unknowingly spreading the virus.

Those who believe they have symptoms can book a test at nhs.uk/coronavirus or by calling a new national helpline number, 119.