Sewage from London is being checked for signs of coronavirus.

A government-led project is successfully detecting traces of coronavirus in sewage, providing early warning for local outbreaks across the country, and sharing data with NHS Test and Trace.

The programme, announced in June, has now proven that fragments of genetic material from the virus can be found in wastewater. This can then indicate where a local community or an institution is experiencing a spike in cases.

Wastewater at Thames Water sites in Bexley, Croydon, Enfield, Hounslow, Kingston-upon-Thames and Newham are testing for the virus.

Results can provide local health professionals with a clearer picture of infection rates by identifying where there are high numbers, particularly for asymptomatic carriers and before people show symptoms. Local authorities to take early action to slow the spread of the virus.

Data will be shared with NHS Test and Trace and inform where new outbreaks may be happening. It means that public health leaders can speak directly to institutions where there may be spikes in infection. Those institutions would then encourage people to get tested or take extra precautions.

The project has already worked successfully in south-west England, where sewage sampling showed an increase in coronavirus material despite relatively low numbers of people seeking tests.

This information was passed to NHS Test and Trace and the local council, which were able to alert local health bodies to the increased risk and contact people in the area to warn of the increase in cases.

Testing has now been rolled out across more 90 wastewater treatment sites in the UK. This includes 44 plants in England covering approximately 22 per cent of the population. There are plans to expand testing.

Environment secretary George Eustice said: “This is a significant step forward in giving us a clearer idea of infection rates both nationally and locally, particularly in areas where there may be large numbers of people who aren’t showing any symptoms and therefore aren’t seeking tests.

“NHS Test and Trace is able to use the science to ensure local health leads are alerted and can take action.”

“We are continuing to look at how this programme can be refined as one of the many measures we’re using to slow the spread of the virus and protect local communities.”

Health and social care secretary Matt Hancock said: “This initiative is just one example of how we are working across government and with local partners to find innovative, new ways to track the outbreak, slow the spread of the virus and save lives.

“Monitoring and sampling wastewater offers another tool to help us identify outbreaks early on – helping NHS Test and Trace and local authorities target hotspots quickly and effectively.

“As we see an increase in cases across the country, it remains vitally important that everyone continues to follow Hands, Face and Space, gets a test and self-isolates if they display any coronavirus symptoms and follows the advice of NHS Test and Trace.”

Separate work carried out by the National Institute for Biological Standards and Control also identified coronavirus material in London sewage in February. This was before any cases were recorded in the capital, providing further evidence of the effectiveness of wastewater monitoring to detect infection rates. High levels of virus material were detected in March and April followed by a considerable decrease in May and June, reflecting the impact of national lockdown measures on virus transmission.

The World Health Organization is clear that the likelihood of coronavirus being transmitted via sewerage systems is extremely low or negligible.