Tributes have been paid to Jack Merritt, 25, and Saskia Jones, 23, who died, as well as to those who helped after the incident in London on November 29 last year.
Mr Merritt and Ms Jones were stabbed by convicted terrorist Usman Khan during a prisoner rehabilitation event.
In a pre-recorded address, the Rev Canon David Parrott, guild vicar of the Church of St Lawrence Jewry and chaplain to the City of London Corporation, paid tribute to those affected by the attack.
In the virtual act of remembrance, broadcast online on Sunday, he asked the public to remember the staff and attendees of Fishmongers’ Hall on the day of the incident, and the first responders who came to their aid.
He said: “For those who rush toward danger, bringing hope and comfort.
“For those who serve, protect and guide others to safety.
“For those who risk their own lives for the sake of others.
“For all for whom that day remains a traumatic memory.”
Colleagues of the victims are also marking the anniversary in an event organised by Cambridge University’s Learning Together programme, of which Mr Merritt was a course co-ordinator and Ms Jones was a volunteer.
Ruth Armstrong and Amy Ludlow, co-directors of Learning Together, said in a joint statement: “Our thoughts are with everyone who was there with us that day, and all who have been impacted.
“We grieve especially for the loss of our inspirational colleague Jack, and our brilliant alumna Saskia.
“Their families and friends are uppermost in our hearts and minds.
“We stand with our whole community, determined to play our part in building towards a better world for us all.”
Cambridge University vice-chancellor Professor Stephen J Toope said Mr Merritt and Ms Jones were in the thoughts of the university community, as well as their families, friends and colleagues and those “who lived through the horror of that attack and the trauma of its aftermath”.
He said: “A year ago our university community was shocked, horrified and profoundly saddened by the senseless attack at an event hosted by the Learning Together programme.”
London mayor Sadiq Khan said the recent rise in the national terrorism threat level and an increase in online extremism are “reminders that challenges lie ahead”, but assured the public that police are “working harder than ever to counter that threat and keep Londoners safe”.
He said: “On the first anniversary of the terror attack at Fishmongers’ Hall and London Bridge, we will be taking the time to stop, reflect and remember the two innocent people who lost their lives – Jack Merritt and Saskia Jones – and the principles they stood for and the hope they inspired.
“They will forever be in our thoughts, as will the families and friends of all those affected.
“I want to pay tribute to the heroic efforts of our emergency services and the heroism of ordinary Londoners who ran towards danger that day to help save the lives of strangers.
“The way that our city responded and stood united in the aftermath of the attack showed the world once again that those who seek to divide us and destroy our way of life in London will never succeed.
“The best way to defeat hatred is not by turning on one another, but by focusing on the values of decency and mutual respect that bind us together and will always prevail.”
Khan, 28, was out on licence when he attended the event near London Bridge, armed with two kitchen knives and wearing a fake suicide vest.
He was tackled by members of the public with a narwhal tusk, a decorative pike and a fire extinguisher before he was shot dead by police on London Bridge.