Number 10 backs lateral flow Covid tests after leaked emails revealed accuracy fears

Henry Bodkin
·2 min read
A man walks past a lateral flow testing centre at London Bridge - Tolga Akmen/AFP
A man walks past a lateral flow testing centre at London Bridge - Tolga Akmen/AFP

Downing Street has insisted lateral flow tests are "accurate" after leaked emails warned that they may only pick up two per cent of Covid cases.

A Number 10 spokesman said the rapid turnaround technology was proving "incredibly useful" at picking up asymptomatic infections despite scepticism among many scientists.

Some four million lateral flow tests were conducted in England in the week to April 7, according to official figures, and the number is expected to rise as all adults are encouraged to take two tests a week.

Schoolchildren have been using the devices for regular asymptomatic testing since they returned to the classroom in early March.

On Friday, The Guardian reported the contents of leaked emails between Department of Health and Social Care officials which suggest they are considering scaling back the programme due to the high rate of false positives.

Ben Dyson, the executive director of strategy, wrote: "As of today, someone who gets a positive LFT result in (say) London has at best a 25 per cent chance of it being a true positive, but if it is a self-reported test potentially as low as 10 per cent (on an optimistic assumption about specificity) or as low as two per cent (on a more pessimistic assumption)."

However, Downing Street hit back at the claims. A spokesman said: "Lateral flow tests have been rigorously evaluated, and we believe that they are both accurate and incredibly useful in terms of being able to spot asymptomatic cases of the virus.

"We know now this can be one in three people and it therefore allows us to identify possible contacts of those people and ultimately helps us to reduce the spread and the transmission of the virus."