Wondering if colleague did this on purpose

No, but you could have said 'Excuse me, I'm expecting guests at 12 and need to check if they have arrived'.

So you told your colleague what room to find you in when your guests arrived and they didn’t come and tell you?

I don’t understand the benefit to them for doing that? All sounds a bit odd, do you not have messenger/ emails so your guests could have contacted you to say you’d arrived?
could you not have told your guests what meeting room
you were in?

all sounds a bit shambolic tbh

It was a bit of an expensive mess, and, as others have said, arguably not sensible of you to just assume that your important visitors were late when they didn't appear by 12, rather than going to reception to look for them or phoning their mobiles.
Rather than getting this junior colleague into trouble (whose job it isn't to find you anyway), how about creating a failsafe process to follow when visitors are expected? And sort out who is responsible for bringing together staff and visitors. If this woman didn't bother to find you because she was annoyed at being asked, that is a weak spot in the organisation that needs sorting out.
I can imagine how furious you are (like I was when a medical receptionist told the doctor I had not turned up for an important appointment. I arrived early and then popped out for five minutes, then come back and was sitting a few feet away from her desk, but she didn't look round to check, just told the doc I had 'gone away'.).

Yeah - you were expecting people to arrive and they didn't, so neither you nor your boss went to find them. Weird.

have not read all your posts but you do have a lot of excuses.

for important meetings for SURE you tell senior consultants that you have to stop now and go and greet the guests. For SURE you position other colleagues to greet the guests too, with you or without you.

You adopt a belt and braces approach, and if it goes tits up you don't blame others.

So lessons learned, reschedule and do it properly next time.

No.

She might agree with you but she certainly doesn't "get it".

Bit weird - they're internal clients? Why didn't they just go to the booked meeting room themselves?

But otherwise I would have told the senior consultant who you had a meeting with, that they won't tolerate lateness, and that you're free until 11:55. I'd have left if you didn't turn up by 12:10 too.

Bottom line is that your carefully arranged meeting didn't happen and the company will lose money as a result. You can blame your colleague and (weirdly) defend the senior consultant as much as you like, but this could all have been avoided had you double-checked whether the other attendees had arrived, rather than relying on someone who 'has form for doing things to prove a point'. Why take the risk? Your employer is unlikely to give a shit that Sandra didn't tell you the client had arrived, or that the senior consultant is 'set in his ways' - it all just sounds like excuses. They will give a shit about the cost to them though and it'll be you that they blame.
Not to say that you shouldn't find out if Sandra stitched you up and, if so, deal with her. She sounds like a piece of work....

"... She was in the building, prepared, had told her team where she was and was going to come as soon as called.

OP was fine"

No she wasn't.

She hadn't told the person most likely to meet the meeting attendees on arrival!

As that person wasn't aware that the OP was actually in on what for the OP is a non-working day, this is mostly down to the OP.

(And down to the "senior consultant" who is so set in his ways and on no account can be inconvenienced in any way...)

Isn't it called projecting?

This is crazy. You needed to inform the member of staff who does the fetching that you are expecting someone. Even more so as it’s not usually your working day!
(You also come across as thinking yourself very superior to this person. You should treat everyone with respect regardless of their role. You are clearly in the ‘she JUST does admin brigade when actually you know little about her wider role in the company)

And again...

And this ^

@AGameOfPatience :

"a) You don't usually work Fridays and I think I'm right in saying that you didn't tell this person - the one you would ordinarily expect to shepherd guests - that, unusually you were in fact in, and where. You only told your team. If so, that is not great planning on your part and this woman is not a mind-reader.

b) You did not alert this person to the fact you were waiting for important clients/colleagues full stop, yet expected her to be available to facilitate their arrival, fetch you, and understand the ramifications of failing to do so. That is also poor planning given that you knew how crucial this meeting was.

c) You failed to extract yourself from your prior meeting on time on the presumption that someone else would keep your appointment and schedule for you. You've unfairly and unwisely decided to rely on nebulous "others" to ensure you link up.

d) You also seem to lack polite assertiveness with your senior consultant from whom you should be able to excuse yourself for your next meeting."

And this ^

Sounds to me like you are determined to blame her for your own failing. Even Senior Partners/CEOs are human beings who can understand you have to leave or take 2 mins to make alternative arrangements.

And this ^

(We can conclude that the OP never told her because the OP has previously said that this person knows that the OP doesn't work on Fridays so she might have thought it was a mistake thet these people thought they had a meeting with the OP)

This ^

(Although I'm not sure the meeting attendees were in the same building)

Why on earth didn't you tell the person whose job it is to 'receive' people that you were expecting guests? Everywhere I've ever worked that's been standard practice - you tell reception who you're expecting and let them know who to contact when they arrive.

And even more inappropriate and downright weird to not go looking for them when it’s 12:05.

I can’t help noticing you’ve skipped answering whether you bothered to tell this person - arguably the person who needed to know - that you were in the office today, expecting guests, and where to take them when they arrived.

…for this very important meeting that you didn’t appear for until 10 minutes after the scheduled time.

You didn’t need to sit in your office staring into space for 15 minutes or wait by the elevator. Excusing yourself from your prior meeting at 5 ‘till to “go make sure the conference room was ready and you have your materials” and going up front at noon or a minute after check if your guests have arrived is the right choice for an important meeting, however. Part of being senior is helping set tone for he department, so you do need to be proactive, show respect for your colleagues’ time (including the junior ones), and take responsibility for what you should have done better before blaming others.

The same for my office...........but its a huge corporate office with procedures and security in place.

The OP must work for a pretty small outfit and I'm interested to know if random people can just walk in? Who buzzes them in? Presumably security? Or some kind of caretaker? Does security just phone upstairs to whatever extension number they say they are meeting and the visitors have to wait in the lobby until someone comes down to them?

So.......you know she's dodgy and isn't a great team player

Yet knowing this and knowing it was Dodgy Worker who would greet the team you'd been organising to meet SINCE JULY......you waited til 12.10 to start the meeting

And then were horrified that they'd buggered off

How odd 🤔

How very odd 🤣

They were expecting to meet you.
They'd made all arrangements with you.
The impression they got was that you were AWOL at the meeting time, whether or not you thought you had made it clear what to do to someone else who was not really beholden to you.
Who will they feel was it who stood them up, you, or apparently the nearest thing to a reception colleague, but not actually a receptionist?

And yet, if she'd gone out at 12 (or a minute past) instead of 12 minutes past, she would have been fine. You know, since the meeting was scheduled to start at 12 and not quarter past.

A normal person would have wrapped up the first meeting at five to and said, "I'm sorry, I've got that other meeting at 12 but please do email me if there's anything you think we haven't covered and I'll pick it up as soon as I can."

You wouldn't rely on a junior or your team to find you, you can't delegate your own timekeeping and take people away from their jobs to try to. Plus juniors hate interrupting meetings.

Sorry, so you had a meeting booked for (I assume) 12 -1, they turned up, couldn't find you, left after 10 minutes, then ignored your phone calls for 30 minutes even though they were meant to be in a meeting with you? And they didn't try and ring you? What kind of business are you working for???