Prince Philip, Duke of Edinburgh is in hospital

News 24 had its own output and studio, so don't think Peter would have been presenting on News 24 when it broke, unless he was on ready.

It was Philip Hayton on BBC News 24 that evening. Then there was a joint news special presented by Peter Sissons from N6 before News 24 carried on in N8 with Chris Lowe and Anna Jones as usual.

I also remember Graham Miller was presenting the ITN News Channel at the time the news broke and it was Mary Nightingale on ITV News duty. She had just finished the Weekend News before having to return to the air with the breaking news about the Queen Mother.

And Peter didn't join News 24 as a regular presenter until a year later in 2003.

Just out of curiosity, were the presenters on the BBC/ITV/Sky news channels wearing black in the run up to the announcement of the Queen Mother's death?

Mary Nightingale was wearing light grey as she just finished the scheduled news bulletin when she was told of the news, and she was given until the end of the ad break to prepare herself. As she states in the Newsflash documentary, she felt the backlash towards Peter Sissons was unfair, especially as she was wearing something more "unsuitable".

I look back now and think it was unfair. I guess there was strong anti BBC sentiment in the press coverage.

Yep. I'm not 100% sure because I've not seen the documentary in a while (and I do need to go back and watch it again), but IIRC there wasn't really any build-up to the notification of her death. It was a regular news day until the story broke, which was probably why the start of the BBC's coverage was a bit disorganised, and why IRN had their infamous "finger troubles".

Luckily our very own Larry the Loafer uploaded said documentary, and here is the part about the Queen Mother:

Actually nice that for once it was the man rather than woman getting an unfair backlash for their choice of clothing.

I do think what happened with the Queen Mother is more an indicator of what will happen with Prince Phillip. If it breaks early evening I'd expect a couple of hours of reaction before a return to normal programmes then a tribute show later in the evening and extended news, with not too many schedule changes in the days ahead other than for the funeral.

If it breaks early in the morning the BBC will probably have news through to lunchtime (which nowadays is just switching the BBC1/2 schedule) then relative normality from there on other than perhaps an extra news special or two and an evening tribute. ITV will likely allow their daytime shows to largely handle it - they're generally good at taking a more "people" based perspective, although that sort of thing usually works better the morning after than in the immediate aftermath of the news.

More likely it's something they wouldn't do for Prince Phillip but perhaps would for the Queen, or the Prime Minister.

I've changed my mind about the logo ident; now I think the indigo/gold 'Event Safe' ident is the one most likely to crop up.

I think that is more than likely. Depending on the time of day, there will be a few hours of News on both BBC One and ITV, with BBC Two taking the initial simulcast, and breaking off after about an hour, and either take BBC One's schedule, or a slightly altered version (ie gentle programmes such as Escape to the Country, Antiques Road Trip), and if taking Pointless later in the day, a possible change to the billed edition, to make sure there is nothing offensive, or too merry for the occasion. It wouldn't surprise me if they have a repeat on hand ready to do so. I think the One Show would go ahead, but hastily edited (possibly extended to an hour) and be used as a tribute, have guests talking about their memories of the DoE (eg Jennie Bond, possibly a minor royal such as Mike Tindall, and a historian. Not sure about EastEnders, but probably an obituary in the 8pm slot, and pull any unsuitable shows that may be on.

As you say ITV would probably let the likes of This Morning and Loose Women handle it. I'd expect an extended Lunchtime News, not entirely sure about the quizzes but I think they'd be OK to air, but avoid any royal questions. I think the soaps would air, but possibly with Emmerdale delayed until after an extended Evening News, with ITN's obituary taking up the bulk of the night.

C4 and C5, I'm less sure about. They'd probably break into the schedules, but I don't know if they'd have their own obituaries. However, I know they've done plenty of royal documentaries over the years, so they'll probably be repeated if pulling their schedule.

This is all just speculation mind.

As Philip is quite high up in the OBIT list, I’d expect pretty-much wall to wall coverage all day on all PSB channels, news channels and on main satellite channels at least a periodic message about tuning to a news channel for at least the first day. After that who knows? All I do know is that it’ll probably be way more intrusive than the flights of fancy currently being speculated.