Didn't think schools were this strict these days

Grandma70s, I wrote a very long post trying to explain why I felt this way, but decided I was giving away too much personal information on a public forum.
There are young children who have unsupervised access to adult TV programmes and computer games, which definitely affects their perception of what is acceptable behaviour both in and out of the classroom.
We just have accept that some of us we have differing opinions on doing PE in underwear.

If that is the case, Marydoll, we (society) have become more prudish. Why on earth should a very young girl be worried that a boy might see them in their underwear? Who has made her think like that? Why are times different from “when we were young and innocent”? That’s exactly what I was asking.

It's nothing to do with being prudish. Despite being young, some children are self conscious about their body and being seen in their underwear. I've had 7 year old girls hiding under a table to get changed at PE "in case a boy sees them".
I'm not in the least bit "incensed", just concerned about respecting the dignity of a child, especially the child who has been wearing the same clothes and underwear for a week. Children can be so cruel to each other and
Times are very different from when we were young and innocent.
The bottom line is that in this day and age that no child should do PE in their underwear.

I agree, BlueBelle. When did we become such a prudish nation? 7-year-olds should have no self-consciousness about their bodies.

but I don’t think my grand daughter will be forgetting her kit again ...well it’s worked then hasn’t it ?
I think the worse thing is that a 7 year old will have been embarrassed by all this fuss Knickers cover a child, I really don’t understand why you are so incensed

I don't think the teacher will ever make that mistake again. I think your DD the right thing.

I don't think the teacher is inexperienced

Well, my DD has reported it, hence the reply that the teacher thought she was wearing these modesty short type things under her uniform. But I don't think my DGD will be forgetting her kit again!

I know that I would be reporting it, if only to make sure it doesn't happen again. Is the teacher inexperienced?

You are quite right. It wouldn't have happened in my class. It is important to preserve a child's dignity, regardless of sex. No child in my class has ever done PE in their underwear. Unfortunately there are teachers who would allow it. It's up to the management team to ensure there is consistency across the whole school.

I appreciate that, but my DGD isn't exactly a young child. She's old enough to make sure she's got her PE kit, but at the same time old enough not to have to be embarrassed like that! I know teachers have a hard time, but I think its excessive what happened

To be honest, I suspect the teacher was harrassed and is using the shorts excuse as a get out. I may be doing him\her a disservice.
Getting young children ready for PE is a nightmare. There are always children who can't undress themselves, untie laces etc. Before you know it, half the PE time is gone.
I don't mean your GD, but the teacher was probably distracted and didn't really think about the consequences.
You have to ask yourself if it was just a one off, is it worth making a fuss? I'm not in any way condoning what the teacher did. They should have checked your GD was suitably dressed. The minute it was obvious she was in her underwear, teacher should have told GD to get dressed again.
To this day, to my utter shame, I remember being really harrassed and a child who was was constantly out of his seat came out to my desk and interrupted for the umpteenth time. He muttered something, to which I replied, " Oh, that's nice, now go and sit down." What he had actually said was" My granny's house burned down last night." ☹️ We are all human.

Is there anything my daughter can do? Is it worth complaining or anything do you think?

Yes!

But shouldn't the teacher have made sure she was wearing something suitable before getting her to undress?

Apparently it is common place at my DGD's school. Hence why it was assumed she was wearing them!

M&S sell them for wearing under school dresses. In all my years of teaching, I never came across a child wearing modesty shorts.

Apparently the teacher thought my DGD was wearing modesty shorts under her uniform, so wasn't actually expecting her to attend the lesson in her underwear when told to take her uniform off!
The thing I am wondering is, what are modesty shorts?

And my last paragraph refers to juniors. Certain garments were so popular as to be almost fought over!

Were, NOT we’re!
I do wish I could edit!

Grand tante - if it’s going to go it’ll go however you mark it.
In an exclusive and pleasant preprep school a cricket bag disappeared with all its expensive contents. In that school everything is marked. The cricket sweater even has embroidered initials. Extensive searching never unearthed the bag.
When I taught infants in the ‘60s indoor PE was always in vests and pants. When I had an E2L class I discovered some girls did not wear pants under a shalwar. I showed them what knickers were, they found the word highly amusing and we’re wearing them a day or two later all ready for the next PE lesson. And it was rare for any of the hundreds of primary aged (4-11) I taught not to enjoy PE.
I always stocked up on shorts and tee shirts from charity shops and jumble sales (regularly washed) for anyone who forgot their kit.

My lips are sealed now, bluebelle. Thanks. I'm out.

I read that this thread is on Twitter be careful talking about your knickers

Too public for me, even as a child. My family never wore just our knickers, even indoors with just our mum there.

Wasn't really in public, though. It was at school