Coronavirus has made many people across the country feel powerless, with lives restricted and rules preventing individuals doing the things they love.

After the Government's recent announcement that England would be placed under a coronavirus three tier alert system, it would not be wrong for people to start questioning how these crucial decisions are being made.

London was placed in Tier 1, 'medium risk', but the Mayor of London Sadiq Khan has already hinted that London is just days away from entering the 'high risk' Tier 2 level in which meeting people from other households indoors would be banned.

One of Pubic Health Englands (PHE) roles is to ensure that it has the right information available to make informed decisions and put strategies in action.

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To help understand the spread of Covid-19, PHE uses a wide variety of real-time data at both local and national level.

Data to establish coronavirus prevalence in the community and which demographics are being affected is gathered from a wide range of sources, such as GPs, hospitals or even Google searches.

In a recent blog from PHE it said: "Surveillance systems are chosen so they can be measured regularly and consistently. No single piece of data tells the whole story of any outbreak, nor can any system provide a definitive figure for exactly how many people could have Covid-19 as many will have a mild illness and never report it to the health services.

"By bringing together a wide range of data we can make well informed judgements about emerging trends, geographical variations and the groups of people most affected."

Here are the different ways that PHE build its understanding of coronavirus in London and England:

Across the country teams of experts and scientists in infectious disease outbreaks are on the lookout for outbreaks in venues like schools or care homes.

The information gathered is used to build an understanding of the pandemic movement and initiate responses both locally and nationally.

Internet-based surveillance also tracks the volumes of people searching for typical symptoms of coronavirus on search engines like Google, and PHE look for evidence that numbers of these searches are increasing above normallevels.

PHE also use an online FluSurvey which is completed by members of the public and tracks self-reported respiratory symptoms.

The tool has been adapted to monitor community prevalence and the amount of symptoms related to Covid-19.

GPs across the country submit data to PHE regarding coronavirus in the community.

PHE monitors the daily number of GP consultations where patients have presented a range of respiratory symptoms including Covid-19 cases.

Around 4500 GP surgeries are submitting data daily with out of hour contact also being recorded and analysed.

Cases in hospitals are also monitored by PHE to help build a picture of the prevalence of coronavirus in the country.

The Emergency Department Syndromic Surveillance System monitors the number of daily visits (from people suffering with respiratory illnesses) to a network of around 70 emergency departments across England.

Another system called the Covid-19 Hospitalisation in England Surveillance System, or CHESS, was set up specifically for surveillance purposes and is used to help estimate the daily rate of new hospital admissions for people with coronavirus.

PHE also use a laboratory surveillance tool for monitoring major respiratory viruses circulating in England.

Samples from laboratories based in all parts of the country are analysed to gather the percentage of tests that are positive for Covid-19.

Changes in the proportion of tests that are positive are an early indicator of changes in the number of infections.

Information on the number of people who have been hospitalised with confirmed Covid-19 in England and subsequently died is recorded along with as monitoring any abnormal increases in other causes of deaths that may be linked to the pandemic.

PHE also looks at confirmed cases of Covid-19 across the world including the overall number of deaths.

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Google searches help infectious disease experts track the spread of coronavirus - My London