Families of those killed as well as survivors of the attack at the Manchester Arena on May 22, 2017, were also at the service, along with rescue workers who were first on the scene of the tragedy.

As well as the 22 killed, ten of them aged 19 or under, a further 800 were injured physically or psychologically, and many of the rescue workers have been left traumatized.

A one-minute silence was observed in the cathedral, across the city and in public buildings across the country.

Buses in Manchester pulled over by the roadside, and MPs in the House of Commons stood in silence.

High security was in place in and around the city center, with armed cops on duty as many people gathered in public squares to commemorate the anniversary.

The attack came at the end of a concert by U.S. singer Ariana Grande who sent a message Tuesday to the people of Manchester.

It read: "I love you with all of me and am sending you all of the light and warmth I have to offer on this challenging day."

May, writing Tuesday in the Manchester Evening News, said the targeting of the young and innocent as they enjoyed a care free night out in the Manchester Arena was an act of sickening cowardice.