People across the UK have observed a minute's silence and shone a light to remember victims of the pandemic on the anniversary of the UK's first lockdown.
Across the country, Britons marked the anniversary of Boris Johnson's first lockdown with a minute's silence in memory of those who have died during the pandemic.
At 8pm people were encouraged to stand on doorsteps with phones, candles and torches to signify a "beacon of remembrance".
The London Eye, Tate Britain, Blackpool Tower, Belfast City Hall, Liverpool Town Hall and the parliaments in Wales, Scotland and Northern Ireland were among the other landmarks lit in yellow to mark the occasion.
A candle in a lantern was also placed outside 10 Downing Street.
The Queen has reflected on the "grief and loss felt by so many" as she led tributes, sending a message to the hospital where the Duke of Edinburgh had heart surgery.
"As we look forward to a brighter future together, today we pause to reflect on the grief and loss that continues to be felt by so many people and families, and pay tribute to the immeasurable service of those who have supported us all over the last year," the Queen said.
The note, along with the bouquet of irises, tulips, mixed narcissi and ranunculus, was carried to St Bartholomew's Hospital in the city of London from Windsor Castle, where the Queen and Prince Philip have been staying during the pandemic.
The Duke and Duchess of Cambridge took part in a private moment of reflection in Westminster Abbey, observing the minute's silence in the Shrine of St Edward the Confessor.
MPs and peers in both Houses of Parliament and ministers in the devolved nations marked the anniversary at midday, while cathedrals in Blackburn, Winchester, Gloucester and York Minster also fell silent.
NHS and social care workers also joined the pause for reflection.
More than 300 organisations, community groups and charities took part in the event organised by end-of-life charity Marie Curie.
Matthew Reed, the charity's chief executive, said: "The emotional toll of the grief so many of us have faced, at a time when so few of us have been able to connect with friends, family and community in the ways we normally would, is immeasurable.
"The work of so many communities, to recognise the day, sent a strong message to those hit hardest by the death of a loved one - they are not alone.
"From neighbours shining a light on their doorstep at 8pm, to political leaders respecting the minute's silence, our nation has shown a vital acknowledgement of the challenges bereaved people have been facing during this difficult year."
He said the charity wanted to make the national day of reflection an annual event "to recognise the impact of bereavement for any cause".
A year since his dramatic "stay at home" TV address to the nation, the prime minister said the past year has been one of the most difficult in the country's history.
And it comes on the day new figures from the Office for National Statistics showed a total of 149,117 people have had COVID-19 recorded on their death certificate since the pandemic began.
Marking the anniversary, Mr Johnson said: "The last 12 months has taken a huge toll on us all, and I offer my sincere condolences to those who have lost loved ones.
"Today, the anniversary of the first lockdown, is an opportunity to reflect on the past year - one of the most difficult in our country's history.
"We should also remember the great spirit shown by our nation over this past year.
"We have all played our part, whether it's working on the front line as a nurse or carer, working on vaccine development and supply, helping to get that jab into arms, home schooling your children, or just by staying at home to prevent the spread of the virus.
The PM later told a Downing Street news conference that a permanent memorial to those who have died during the pandemic will be built "at right moment".
Labour leader Sir Keir Starmer was among those who joined the minute's silence to remember those who have lost their lives.
Earlier, he tweeted: "As we mark one year since our country entered the first lockdown, my thoughts are with all those who have lost loved ones since the pandemic began."
First Minister Nicola Sturgeon told the Scottish Parliament: "A year ago today we all felt scared and uncertain - we did not know exactly what lay ahead or how long it might last.
"But we did know we had to come together to save lives and I know I will never be able to adequately express the depths of my gratitude for all the sacrifices that have been made by so many over the past year."
Northern Ireland's Deputy First Minister Michelle O'Neill said balancing the need to protect lives and livelihoods had been a "nightmare".
"I think there'll be plenty of time for reflection, I think today is about individuals, their loss, their experience and we're focused on that," she said.
In Wales, First Minister Mark Drakeford said COVID had "turned our lives upside down", but the public had united "in the darkest of times".
"It's been a year of many sad stories, but it's also been a year of determination and bravery, from so many people all across Wales who have worked to support us and keep us safe," he said.