Labour has blamed fresh "chaos" over coronavirus after applicants for a 'test and trace' programme were wrongly told it had been put on hold.
Officials have ramped up recruitment for the crucial contact tracing service from just 1,500 people last week to 17,000 by yesterday.
The service and a companion app are now due to launch for the beginning of June, back from the original date of mid-May.
But the Mirror and other journalists were contacted by perplexed applicants - who received a "false" email claiming the programme was "on hold".
In an e-mail from Kent-based recruitment firm HR Go, dated one minute past midnight on Saturday, they were told: "Unfortunately earlier today the roles were put on hold.
"This is due to a delay in the launch of the ‘Track and Trace’ App itself while the government considers an alternative App."
Both HR Go and the government are adamant that the e-mail contained false information and they are trying to work out how and why it was sent.
The Department of Health said work on track and trace is progressing and there is no alternative app.
But Shadow Health Secretary Jon Ashworth accused the government of a "chaotic" approach.
He told The Guardian: "Test, trace and isolate is fundamental to managing and controlling this virus and safely easing lockdown – yet the government’s approach has been increasingly chaotic, with misstep after misstep."
The army of 'contact tracers' will be crucial to nipping any new outbreaks of coronavirus in the bud as lockdown starts being eased.
The 15,000 call handlers and 3,000 clinical experts will work alongside a new NHS app, which will track people's movements and tell them if they've had close contact with another app user with Covid-19.
Anyone with symptoms will be advised to self-isolate at home and report symptoms to the app.
Those who've had contact with them will be told to stay in isolation, and/or get a test delivered to their home or a drive-through centre.
Job adverts show the call handlers are being recruited by private firms and will be paid the over-25s' minimum wage of £8.72 an hour.
They will be expected to use government track and trace software on their own laptop or PC.
Top Tory Michael Gove claimed yesterday that almost all the contact tracers had been recruited in less than a week.
His Cabinet colleague Brandon Lewis said only 1,500 people were in place as of early last week.
But Mr Gove said: "It’s now the case that more than 17,000 people have been recruited for contact tracing so we’re on course to meet that target."
Mr Gove admitted however that the test and trace programme is now due to restart by the beginning of June - not mid-May as ministers first pledged.
John Parkinson, chief information officer at HR Go, told the Mirror the e-mail was sent "to a temporary applicant".
He added: "What has been said is a miscommunication and false.
"We are not aware of any reason why Track and Track would not being continuing as it should.
"We will be communicating with the applicants directly to correct that once we have completed our internal investigations."
A Department of Health and Social Care spokesman added: "This e-mail is inaccurate and we are trying to ascertain its origin because it is both wrong and could cause confusion.
"Our recruitment of contact tracers for our online and phone-based contact tracing service continues at pace. For those already recruited, their training programmes continue.
“The NHS contact tracing app is not on hold – and it would be completely wrong to suggest otherwise.
"There is no alternative app and the NHS continues to work constructively with many other organisations that are helping to develop and test the NHS COVID-19 App."
