This week marks 100 days since the World Health Organisation (WHO) was alerted to a mystery illness in China which saw a handful of people fall ill in the city of Wuhan.

As the UK enters its third week in lockdown, and with more than one million cases reported around the globe, the PA news agency looks at some of the key dates of this pandemic.

– December 31 2019:

The outbreak of a mystery respiratory illness in the central Chinese city of Wuhan leaves 27 people with viral pneumonia – seven of whom are in a serious condition in hospital. There are early comparisons with the Sars outbreak of late 2002, however authorities say the cause is unclear and urge people not to panic. The WHO is informed.

– January 3 2020:

The number of confirmed cases rises to 44, most of which have been traced to the South China Seafood City food market in Wuhan, where offerings are reported to include wild animals that carry viruses dangerous to humans.

– January 8:

Chinese state broadcaster CCTV identifies the possible cause as a new type of coronavirus – one of the main causes of the common cold, but which normally only produces mild symptoms.

– January 11:

A 61-year-old man with “severe underlying health issues” becomes the first person to die from the outbreak. Chinese officials say the threat of human-to-human transmission remains low.

– January 17:

The US announces it will begin screening passengers at Los Angeles, San Francisco and New York City’s John F Kennedy airports arriving on flights from Wuhan.

– January 20:

New cases are confirmed in Beijing and Shenzhen, as the death toll rises to three. Authorities in Thailand and Japan identify at least three cases, all involving recent travel from China.

– January 22:

Wuhan goes into travel lockdown, with outbound flights and trains banned, and bus routes closed in an effort to contain the virus. The death toll stands at 17. Meanwhile, the Department of Health decides all direct flights from Wuhan to Heathrow airport will be subject to enhanced monitoring.

– January 23:

Health Secretary Matt Hancock tells the Commons that the NHS is “ready to respond appropriately” to any cases of coronavirus that emerge in the UK. Meanwhile, the UK tests its first 14 patients for coronavirus, five of whom are in Scotland.

– January 24:

The Wuhan lockdown is extended across China countrywide, with transport links shut down in at least 13 cities which are home to more than 36 million people. It comes as the Chinese government announces construction of a pop-up hospital to deal with the steep rise in cases. In the UK, Mr Hancock chairs a Cobra meeting on the Government’s planned response to the virus. Afterwards, he reiterates to reporters on Whitehall that the threat to the UK is “low”.

– January 25:

Chinese New Year is a subdued affair, with more than 1,200 cases of coronavirus and more than 40 deaths. President Xi Jinping describes it as a grave situation.

– January 26:

The Foreign Office updates its guidance to “advise against all travel to Hubei province”, the centre of the outbreak. Britons in Wuhan are told to leave if they can.

– January 28:

The death toll passes 100.

– January 30:

The WHO declares the coronavirus outbreak a global emergency. It comes as China reports more than 7,800 cases including 170 deaths.

– January 31:

The first people in England – two members of the same family – test positive for coronavirus. Meanwhile, Britons arriving on flights from Wuhan are taken into quarantine. A public health emergency is declared in the US. The virus has infected almost 10,000 people globally, with 213 fatalities – all in China.

– February 2:

The first coronavirus death outside of China is confirmed, in the Philippines.

– February 3:

Scientists identify bats are the potential source of coronavirus.

– February 6:

Dr Li Wenliang, a 34-year-old ophthalmologist who was rebuked when he blew the whistle on the potential spread of the new virus in China in December, dies after contracting the illness.

– February 11:

Steve Walsh, a businessman from East Sussex thought to be at the centre of a UK outbreak, says he has fully recovered from the illness. It comes as the death toll in mainland China passes 1,000 people.

– February 12:

The 2020 Mobile World Congress technology show, due to take place at the end of the month in Barcelona, is cancelled over coronavirus fears. It is among the first major international events to be ditched, along with Glastonbury Festival, the Wimbledon tennis championships, and the Eurovision Song Contest.

– February 19:

Passengers are allowed to leave the Diamond Princess cruise ship at the end of their quarantine, after being docked in Yokohama for days following an outbreak onboard the vessel.

– February 22:

Special measures are introduced in towns in northern Italy in an effort to contain the virus, as the first deaths in the European country are confirmed.

– February 24:

The WHO says the planet must prepare for a coronavirus pandemic.

– February 25:

The first schools in the UK are temporarily shut as pupils returning from ski trips in Italy report symptoms. Nationwide closures follow.

– February 27:

The FTSE 100 hits a new 13-month low as the coronavirus outbreak continues to spook traders, with the leading companies seeing £150 billion wiped off their value in four days. The first case of coronavirus is recorded in Northern Ireland.

– February 28:

The first British death from coronavirus – known as Covid-19 – is reported. He was a passenger on board the Diamond Princess cruise ship. The first case of coronavirus is reported in Wales.

– February 29:

The first case of coronavirus is confirmed in the Republic of Ireland.

– March 2:

Scotland confirms its first case of coronavirus.

– March 5:

The first person in the UK dies with coronavirus. The woman, in her 70s, died in the Royal Berkshire Hospital in Reading. A second person, a man in his 80s, dies the following day.

– March 10:

The Cheltenham Festival, one of the highlights of the horse racing calendar, goes ahead despite concerns about spreading the virus.

– March 11:

The Covid-19 outbreak is declared a pandemic by the WHO.

– March 13:

European countries including Austria, Portugal, France, Denmark and Norway begin to ban public gatherings and close schools as the death toll mounts. The first Coronavirus patient dies in Scotland. Top-level football competitions in England, Scotland, Wales and Northern Ireland are suspended.

– March 14:

President Donald Trump announces a travel ban on the UK and Ireland, extending existing restrictions covering mainland Europe.

– March 15:

Number 10 announces daily press briefings on the progress of the pandemic. The Foreign Office advises against all but essential travel to more than 30 countries.

– March 17:

Chancellor Rishi Sunak unveils a £330 billion package to help businesses furlough staff. Similar measures are announced later covering self-employed workers. In other news, public worship is suspended by the Church of England.

– March 20:

Boris Johnson orders pubs and restaurants across the country to close.

– March 23:

Lockdown in the UK. The public is told they will only be allowed to leave their homes for limited reasons, including shopping for food, exercise once per day, medical need and travelling for work when absolutely necessary.

All shops selling non-essential goods are told to close, gatherings of more than two people in public are banned, all events including weddings but excluding funerals are cancelled. And Foreign Secretary Dominic Raab tells Britons travelling abroad to return home while they still can.

– March 24:

The Government launches an appeal to recruit a 250,000-strong “volunteer army” to help with tasks such as delivering supplies and getting in touch with lonely people in isolation. More than 750,000 people sign up to help in the first week of recruitment.

– March 25:

The Prince of Wales tests positive for coronavirus but is displaying only “mild symptoms”, Clarence House says.

– March 26:

The Prime Minister, Princes George and Louis and Princess Charlotte lead the country in a one-minute round of applause for the NHS, as people stand on their doorsteps, balconies and street corners to show appreciation for key workers during the outbreak. It is a gesture which is repeated at the same time a week later.

– March 27:

Boris Johnson and Health Secretary Matt Hancock test positive for Covid-19, while chief medical officer Chris Whitty says he has symptoms of the disease and is self-isolating.

– March 28:

UK deaths from coronavirus reach 1,019 – an increase of 260 in 24 hours.

– March 29:

It is revealed Amged El-Hawrani, a 55-year-old consultant, has become the first frontline NHS hospital worker to die after testing positive for coronavirus. He died in hospital on March 28.

– March 30:

The first person to be arrested on the railways for breaching the new coronavirus lockdown rules is fined £660. However, it later emerges she was incorrectly prosecuted, and the conviction is essentially revoked.

– April 1:

It is announced that 13-year-old Ismail Mohamed Abdulwahab died alone in hospital two days ago. The schoolboy, from Brixton in south London, is the first known child in the UK to die with the disease. He is buried on April 3, with no members of his family present due to their self-isolation. It is also announced that the United Nations “Cop26” climate talks, which were set to take place in Glasgow in November, have been postponed until 2021.

– April 2:

Almost a million people sign up for Universal Credit, the Government’s welfare payments system, in a two-week period – underlining the financial hardship many are facing. Meanwhile, Boris Johnson says he is “still showing symptoms” of Covid-19.

Chinese authorities ease lockdown measures on Wuhan, enabling many to leave their homes for the first time in months.

– April 3:

Matt Hancock, returning from self-isolation, opens the new Nightingale field hospital at the ExCeL in East London. It comes as two NHS nurses – Areema Nasreen and Aimee O’Rourke – are named among those health workers to have died from the virus.

Later, England’s chief nursing officer Ruth May urges people to honour their memory by staying home at the weekend, amid concerns the warm weather will tempt people to break social distancing guidelines. The number of registered cases of coronavirus passes the one million mark.

– April 5:

The Queen addresses the nation in a historic television broadcast, invoking themes of the Second World War by announcing: “We will meet again.”

An hour later, it is confirmed Boris Johnson is admitted to hospital for tests as his symptoms persist. Earlier, Matt Hancock says sunbathing is banned during the lockdown, and does not rule out tougher restrictions if people fail to abide by rules.

– April 6:

Boris Johnson says he is “in good spirits and keeping in touch with my team” after a first night in hospital. Number 10 insist the Prime Minister remains in charge of the country.