One in seven people transferred to the Test and Trace system after testing positive for Covid-19 were not reached in the latest week, new figures show.
It is the largest proportion not reached since October last year and comes as the number of people testing positive rose to its highest total for nearly six months.
Some 14.2% of people transferred to Test and Trace in England in the week ending July 14 were not reached, according to the Department of Health and Social Care.
The figure has not been this high since the week ending October 21 2020, early in the second wave of coronavirus, when it stood at 14.5%.
Only 85.6% of people transferred to Test and Trace were reached in the latest week.
A total of 259,265 people tested positive for Covid-19 in England at least once in the week to July 14.
This is up 33% on the previous week and is highest number since the week to January 20.
The sharp rise in positive cases reflects the impact of the third wave of coronavirus, which is continuing to spread across the country.
The latest data suggests the Test and Trace system is facing pressures similar to those seen during the second wave of the virus last winter.
Just under two-thirds (64.7%) of people who were tested for Covid-19 in England in the week ending July 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 up slightly from 63.0% the previous week, but is the second time since mid-January that the percentage has been below two-thirds.
Prime Minister Boris Johnson had pledged that, by the end of June 2020, the results of all in-person tests would be back within 24 hours.
He told the House of Commons on June 3 2020 he would get “all tests turned around within 24 hours by the end of June, except for difficulties with postal tests or insuperable problems like that”.
Some 475,465 close contacts of people testing positive were identified in the most recent week, of which around nine in 10 (428,001) were reached and asked to self-isolate.
There is likely to be some overlap between these numbers so they cannot be added together, but they suggest that more than a million people in England and Wales were asked to self-isolate in the week to July 14.