The last thing I did before I left the office on Tuesday night was write a short note to the editor of the following day's programme: "If you want a voice out of Homs tomorrow, my old mate Marie Colvin of the Sunday Times is there."
Hours later, she was dead, killed by a Syrian army attack on a building which was being used by anti-government activists as a base for visiting journalists who'd been smuggled in across the border. The award-winning young French photographer Remi Ochlik was also killed; three other Western journalists were injured.
This isn't going to be yet another tribute to one of the bravest and finest journalists of her generation (although Marie Colvin was both exceptionally brave and exceptionally talented). But I think it may be worth reflecting on why war correspondents put their lives in danger and whether the risks they run are worth it.
At a time when the reputation of journalists has probably never been lower (phone-hacking, police-bribing, celebrity-harassing -- you name it, journalists have, allegedly, done it), why not pause, just for a moment, to analyse a very different kind of journalism?
On Wednesday night's programme, the Syrian opposition activist Mahmoud Ali Hamad was adamant: the bravery of correspondents like Marie Colvin is saving lives. If it weren't for their presence, and their reporting, he said, government forces would be killing even more people, with even more impunity.
Marie herself reflected, in an address delivered just over a year ago, on the role of the war correspondent. "Someone has to go there and see what is happening. You can't get that information without going to places where people are being shot at, and others are shooting at you.
"The real difficulty is having enough faith in humanity to believe that enough people ... will care when your file reaches the printed page, the website or the TV screen. We do have that faith because we believe we do make a difference."
The key issue for Marie Colvin, according to Lindsey Hilsum of Channel 4 News, was to make sure that no one could ever say: "We didn't know." When people were being killed, when atrocities were being committed, it mattered to her that someone was there to bear witness and to tell the world.
The vast majority of journalists who are killed each year (46 last year, according to the Committee to Protect Journalists) are local reporters, killed in their home country. Their courage is even greater than that of the visiting correspondent, because they work in the knowledge that their homes and their families are constant potential targets -- and the truth they report is often a truth that their leaders, or other powerful interests, would much rather went unreported.
And as every foreign correspondent knows, the drivers, fixers, and translators who work with them often demonstrate the most stupendous courage. (Only once, in more than 40 years as a journalist, has a fixer walked out on me -- it was in Cambodia, during a military coup, when our fixer decided, quite rightly, that his family needed him more than we did.)
No journalist goes into a war zone believing it will be their last assignment. Risks are carefully assessed, precautions are taken, advice is sought. Only if the risks are deemed acceptable does the reporter head into danger. Every journalist who's been in Homs over the past three weeks, including the BBC's Paul Wood, with cameraman Fred Scott, has taken huge risks. Until this week, their calculation that those risks were within the bounds of what was acceptable seemed to have been borne out.
I have never forgotten the first words that were spoken to me on my first day in my first job: I'd been taken on as a trainee with Reuters news agency, and the then general manager, a big, bluff man called Gerald Long, welcomed us with the words: "I want you to understand one thing right away -- you're no use to me if you're dead."
Marie Colvin knew the dangers even better than most of her colleagues. She nearly lost her life in Sri Lanka in 2001, when she was caught in an army ambush and lost an eye. The man she had replaced as Middle East correspondent for the Sunday Times in the mid-80s, David Blundy, was killed just a few years later in El Salvador.
We should remember, though, that her death was just one of many this week in Homs. As I said on Wednesday's programme: "Most of those who died were people whose names we will never know: some of them civilians struck down by snipers as they ventured out to find food; others, fighters armed with light weapons taking on the full might of the Syrian army."
But the reason the death of a correspondent is worth marking is that it represents the silencing of a voice. And there are few voices as eloquent, or as powerful, as Marie Colvin's was.