There has been a large increase in coronavirus cases in England, newly-released Test and Trace figures show.
On the day after Boris Johnson announced stricter rules on social gatherings, figures show 9,864 new people tested positive for coronavirus in the week ending 2 September.
This represents a 43% increase on the previous week’s figure, when 6,732 tested positive – which marked a 6% rise from the week before that.
The current figure is the highest weekly number since the government’s Test and Trace scheme was launched at the end of May.
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The figures also show that some 30% of close contacts of people who tested positive were not reached by tracers.
In total, 69.2% of people were reached – down from 69.8% in the previous week and the lowest weekly percentage since the scheme started.
Dr Daniel Lawson, a lecturer in statistical science at the University of Bristol, said the figures showed that “the number of new cases will continue to rise rapidly”, adding that the delay in the infection process meant it will be hard to know if government action will stop the spread.
He added: “We must get the infection number per infection (R number) below one to prevent a large second wave which will be impossible to prevent reaching vulnerable populations.”
The figures come as the Test and Trace system has come under criticism for a flaw in its online booking system which tried to direct people to test centres more than 100 miles away.
A senior source last week said a new change that would restrict test centre locations to within 75 miles.
Health secretary Matt Hancock previously said the testing regime was working “well” despite some people being directed to centres more than 100 miles away.
He told Sky News that the issue was part of the reason why the government was investing in trials of 20-minute COVID-19 tests.
Hancock said: “At the moment the system works well. Of course there are operational challenges from time to time but it works well.
“And we’re finding a higher and higher proportion of people in the country who have coronavirus and getting them tests so they can be looked after.
“But absolutely we need to roll out more testing – we have done throughout this crisis and today’s another step in solving some of those problems with the existing technology.”