The performance of the NHS Test and Trace system continues to slide, with just one in seven people having a test at a centre getting their result back in 24 hours.

The new weekly data from the programme shows 15.1% of people who were tested for Covid-19 in England in the week ending October 14 at a regional site, local site or mobile testing unit – a so-called in-person test – received their result within 24 hours.

This is down from 32.8% in the previous week and is the lowest weekly percentage since Test and Trace began.

The figures also show a drop to 59.6% in the proportion of close contacts of people who tested positive who were reached.

This is the lowest weekly percentage since Test and Trace began and is down from 63% in the previous week.

For cases handled by local health protection teams, 94.8% of contacts were reached and asked to self-isolate in the week to October 14.

But for cases handled either online or by call centres, this figure was 57.6%.

The data also shows the positivity rate – the proportion of all tests returning a positive result – has climbed to 7.1% for the week, the highest since Test and Trace began.

According to criteria published by the World Health Organisation, a positivity rate of less than 5% is one indicator that the epidemic is under control in a country.

A total of 101,494 people tested positive for Covid-19 in England at least once in the week to October 14 – a rise of 12% in positive cases on the previous week.

The latest data shows that of 96,521 people transferred to the system, 80.7% were reached and asked to provide details of recent close contacts.

This is up slightly on 79.9% in the previous week.

Labour’s Justin Madders said it was time for ministers to admit that the private companies being paid millions of pounds to help run the system “aren’t up to the job”.

Shadow health minister Mr Madders said: “To have over 40 per cent of people not even being contacted by the test and trace system is an interstellar sized black hole in the Government’s plan to reduce transmission.

“How much longer are we expected to put up with this dangerous failure before ministers admit that the likes of Serco just aren’t up to the job?

“The need for a circuit break is absolutely critical now and that time should be used to fix test and trace once and for all.”

Health minister Lord Bethell said: “We’re rightfully proud of our achievements, as we continue to test more per head that any other European country.

“However, we do know that more needs to be done; to this end, we’re constantly looking for new ways to improve the service, scoping out new technologies, partnerships and ways of working to equip us to better support our people, locally and nationally.”

Interim executive chair of the National Institute for Health Protection, Baroness Dido Harding, said: “Reducing turnaround times is our absolute priority to make sure we are reaching people as soon as possible.

Today’s track and trace numbers show a system struggling to make any difference to the epidemic

“We always need to balance ensuring as many people as possible can get a test alongside ensuring test results are delivered as quickly as possible, and as capacity continues to grow at pace, we expect to see improvements.

“Partnerships across the public, private and educational sectors, alongside rapid advancements in technology and our ongoing recruitment drive, are helping us ensure that we meet our target of 500,000 a day by the end of October.

“Nearly 30,000 testing capacity has been added in the last week, which will result in faster turnaround times going forward.

“Strengthening our partnerships with local public health teams, meanwhile, will further improve the speed with which we are able to trace and contact people in their communities.”

Professor James Naismith, from the University of Oxford, said: “Today’s track and trace numbers show a system struggling to make any difference to the epidemic.”