Truth is under attack like never before, BBC director general Tim Davie told a special church service in London, attended by the Duchess of Cornwall.
Speaking at the annual commemorative service for journalists, held at St Bride's, Fleet Street – the journalists' church – Davie said: "In the disinformation age, truth is under assault like never before. Those who stand up for it most strongly have never been more targeted."
He welcomed the recent award of the Nobel Peace Prize to journalists, Maria Ressa and Dmitry Muratov, "for their fight for freedom of expression" in the Philippines and Russia.
In praising their courage, the Nobel committee said that they considered the two to be "representatives of all journalists who stand up for the ideals of democracy and peace in today's world."
Davie explained: "We know that the physical risks faced by journalists no longer come solely from the front line. Reporters all around the world face escalating dangers, increasing levels of harassment, and ever more subtle modes of intimidation."
He said that in March, the BBC's Beijing correspondent, John Sudworth, had been forced to leave China as "a result of pressure and threats from the authorities."
Over the summer, the BBC's Moscow correspondent, Sarah Rainsford, was expelled from Russia after more than 20 years of reporting. These moves, he said, "were almost unthinkable just a few years ago."
Davie told the service on November 9, that journalists share key beliefs "that truth is the foundation of democracy, that power must be held to account, that those who abuse that power must be exposed, and those who are the victims of that abuse must be given a voice."
He added: "These are the values that bind us. But, more than anything else, what truly brings us together as a family is the compassion and care we have for our colleagues in peril right around the world, and for their families."
Introducing the service, Canon Alison Joyce, Rector of St Bride's said: "The world has never been in greater need of good journalism, and we have never had more occasion to be reminded of the human cost of good journalism than we have today.
"It is our privilege to honour the memories of all those journalists; photographers; film crew; and their support staff, and all who work freelance in the industry, who have lost their lives this past year and to remember in our prayers those who continue to work in situations of immense personal risk in the pursuit of truth. We owe you all an immense debt of gratitude."
Anthony Loyd, war correspondent for The Times, reviewed the media's coverage of Afghanistan over the past 20 years, and urged the media not to withdraw following the Taliban's return to power.
He said: "What happens next in Afghanistan can be influenced to some extent at least by journalists, and especially by editors and executives.
"We have a choice, whether to complete the abandonment of Afghanistan and fade out the media's focus of what happens there next or to persist in reporting from the country in a way that may illuminate the necessity of dialogue with the Taliban as starvation threatens millions."
ITV News political correspondent Libby Wiener read Jesus's words from John's Gospel, chapter 15: "Greater love has no one than this, that someone lay down his life for his friends."
Daily Mirror Editor Alison Phillips read from Martha Gellhorn's 'The Face of War', a collection of the writer's reports from the frontline.
The service came within days of Pope Francis praising the role of journalists. He said: "Journalism does not come so much by choosing a profession, as by launching oneself on a mission, to explain the world, make it less obscure, make people less afraid and look at others with greater confidence."
The Pope encouraged journalists to keep in mind what he considers the three marks of good journalism: listening, going deep and storytelling.
"Journalism does not come so much by choosing a profession, as by launching oneself on a mission, a bit like a doctor, who studies and works so that evil is cured in the world," he said.
During the St Bride's service, Canon Alison Joyce led a poignant prayer for all involved in journalism:
in whose perfect realm no sword is drawn but the sword of justice,
and no strength known but the strength of love:
guide and protect all who seek to bear witness
to the truth of your troubled world;
all who seek to give a voice to the voiceless,
and to tell stories that would otherwise remain untold.
We remember especially this day all members of this profession who have died,
or whose fate is unknown
that you may bless their work,
and strengthen and sustain those who love them.
In Jesus' name we pray. Amen.
Rev Peter Crumpler is a former communications director with the Church of England and author of 'Responding to Post-truth.'