Prime Minister Theresa May and Prince William will on Tuesday join families of the victims of the Manchester Arena bombing at a commemoration ceremony in the city on the first anniversary of the tragedy.
They will attend the service at Manchester Cathedral alongside first responders, civic leaders and some of the scores injured in the suicide attack on May 22 last year, which killed 22 people.
Salman Abedi, a British man of Libyan heritage, blew himself up outside the venue, which had been hosting a concert by teen pop idol Ariana Grande.
"The targeting of the young and innocent as they enjoyed a carefree night out... was an act of sickening cowardice," Theresa May wrote in the city's local paper the Manchester Evening News.
"It was designed to strike at the heart of our values and our way of life in one of our most vibrant cities, with the aim of breaking our resolve and dividing us. It failed."
The prime minister said that "such appalling acts of wickedness" would strengthen Britain's resolve "to defeat such twisted ideologies and beliefs."
Manchester, singer Ariana Grande performs at the One Love Manchester tribute concert in Manchester, north western England, Sunday, June 4, 2017. Source: AAP
The remembrance service will be shown on a big screen in nearby Cathedral Gardens, as well as at churches in York, Liverpool and Glasgow.
It will incorporate a minute of silence at 2.30pm which will also be marked at British government buildings nationwide.
More than 3,000 singers from local choirs, including a group who were at the arena on the night, will join forces later on Tuesday at a "Manchester together" event in a city centre square featuring half an hour of communal singing.
Andy Burnham, mayor of Greater Manchester, told BBC Radio that all those impacted would be "at the very forefront of our minds" during the day.
"We're stronger than we were, we're more together and there is a more palpable sense of community spirit, but underneath the scars are very real and they're very deep," he said.
"We're a city in recovery and we've still got a long way to go."
Ariana Grande, who had just finished performing when the bomber struck outside, shared a message of support for those affected.
The atrocity was one of a spate of terrorist attacks to hit Britain last year - one in Manchester and four in London - that included bombings and deadly violence with vehicles and knives.
