The mum thinks I'm being petty, but I don't want to drive her kid

Stick to your decision. You are the only adult who is looking out for the 14yo. Her mother even sent her to her room for being bullied by her sister!

I cringe to think what her home life must be like.

The 14yr old needs at least one space where she is safe from her sister.

YANBU. I would stick to my guns.

Did the 7 year old actually apologise or face consequences from mum? If not I would expect an apology at the least before allowing her in the car and perhaps mum to come along too to supervise her. Tricky one.

Stick to your guns. Their mum needs to find a way of transporting her own kids reliably by now. It's been a year, why hasn't this woman learned to drive and got her own car if she doesn't think they can possibly be transported any other way?
I think it's a pisstake to expect lifts for years on end anyway.

I'm also confused as to why she sent both kids to their rooms with the 14yo had done nothing wrong. I would also keep giving the older child lifts, mostly so she has time away from a very toxic environment.

Thoughts and prayers for the 7yos teachers and future employers.

As your friend doesn't have a car and is in need of lifts, it's not her place to dictate who gets to go in your car. Her daughter's misbehaving was a distraction you didn't need whilst driving.

Did your friend make the child apologise?

To be honest, it sounds like the 14 year could do with a break from the sister.

When I dropped them off, I told the mum, who later text me to say she had sent both girls to their rooms and that she is very sorry.

Wait a minute... so she punished her 7yo for her mean, poor behaviour choices, in spite of being told repeatedly to stop; and she punished her 14yo for being a 14yo and wearing appropriate clothing?

That poor older girl must already have issues and will clearly understand just how much less her mum loves and cares about her than her little sister. What a horrible woman.

I think a year is long enough. A seven year old deserves a second chance.

Also…could it mean that the 14 year old won’t get to the event either if her sister can’t go?

Absolutely do not move on this at all.
In fact, I would go further and quietly tell the 14 year old that you're always there for her if she needs you.
Punishing both of them for the 7 year olds behaviour is disgraceful.
Poor child.

Spell it out to her that you have committed to this and you wouldn't dream of giving your children mixed messages.

At the core of my parenting my 4 children was they knew if I said something, i meant it.

It made life easier as they 100% believed I would follow through.

It meant they didn't mess about.

I removed the ps4 only once when the boys were bickering rather than negotiating.
It was unavailable all weekend.
It never happened again, they sorted it out between them.

My friends bought 2 ps4's so everyone was happy, but I believe sharing was the better way.

Stick to your guns.

I wouldn’t stay friends with the mum. She’s a bloody awful parent and I wouldn’t want my kids around her horrible 7 year old. So definitely stick to your ground about no lifts as a bare minimum.

No don’t give the 7yo a lift. The mother is clearly not able to discipline the child threrefore she needs to learn from the outside world that her toxic behaviour wont be tolerated. Sounds like the 14yo is lucky to have you, and you probably provide the only kind/empathic adult interaction she has! Protect that. Enjoy your night.

How do you know her behaviour hasn’t changed? Have you seen them and seen the same behaviour recently?

How open were you about the behaviour- did you just say that the younger one was badly behaved or did you say she was being mean to her older sister and seems to do this a lot? Basically, does the mum actually know what the problem is and that it’s ongoing not a one off?

Yes if you decide to relent on your ban go down this route, then if 7yr old doesn’t behave you can calmly pull the car over, get out, open the doors and make the mum and 7 yr old get out . After that she may never ask you for a lift again, which may or may not feel like a win

I don’t think you’re being unreasonable at all!

How long ago did it happen? Has there been a long enough time and realisation from brat features that you did follow through and for her to realise that she has been disadvantaged as a result of her previous behaviour?

If the event is this evening, hopefully the thought and disappointment that she may be missing out, again, because of her previous actions may be enough to focus her mind on behaving appropriately if you do come to the rescue and agree to take her.

If you do, read her the riot act. No warnings. Any mucking around and you’ll stop the car, her mum will need to get in an Uber and fetch her from the side of the road and it really will be never, ever again(!)

The mum has again asked for a lift and it will be difficult for them to get there without someone driving them.

How on earth is this your problem? Regardless of what happened and how poorly she parents her 7yo, I'd be pissed off at her entitlement and 'taker' attitude. You don't exist to chauffeur them around. She needs to use taxis or public transport or some other solution that is entirely her own responsibility.

Why was the older girl punished for her sister's bad behaviour? That is awful parenting. Don't give the noxious 7 year old a lift ever (excluding life or death, I suppose).

They can take a taxi. Their kids getting somewhere is still their responsibility

Id say she can have one more chance, or that the mum needs to come in the car too.

I'd say that I would take the older girl as she's always so well behaved, but you don't feel safe driving when the younger one is so badly behaved.

Some kids change A LOT in a year,so I would probably give it a go but with a 'reminder' first which her mum should deliver.

It's more common than we think,younger siblings being mean to their elder ones.I know cos I had the exact same thing with my own kids.4.5 years difference,eldest has some SN but more importantly,is just naturally a very sweet,calm character.Youngest is fiery and very sharp, very 'cute' but I had to come down very hard on him cos I won't tolerate bullying of any kind. He was 7 also.

It took a yearish to be 100%,was a nightmare but 3 years on they are now very close at 14 and 10,spend a lot of time together Still have the odd fallout but teen will now yell back so more fairly balanced.

I judge the mum for letting it go on,long awaited pregnancy or not.

I absolutely despise adults - parents, teachers and others - who get annoyed at a situation and just punish all of the children involved, whether perpetrators, victims or on the sidelines. They might think that they've just found a lazy, effective way to diffuse the problem; but the falsely-blamed children never respect or really trust them, and they never forget either.

It's your car, you are in charge of who goes in it.

Absolutely take the older one and you be very clear with the younger one that it is because you do not trust her to stick to your rule that in your car people are kind to each other and behave in ways that are safe.

Let her realise that she will miss out if she is mean when you are in charge. then perhaps next time as for her promise of kind behaviour as she will know you mean what you say. (Perhaps for this event, find some way to make being in your car a real treat so the little one really misses out even if mum sorts a lift with someone else.)

Is your friend going too or would it just be the children? I would agree to give a lift to the 7 year old if the mum is there too but make it very clear that if there is any misbehaviour you will kick them both out of the car.

I’m not excusing the behaviour of the 7 year old, but if this was a year ago then she was only 6 at the time and it’s not her fault she’s been brought up with no boundaries. A lifetime ban seems extreme and I don’t think it’s backing down to give another chance after this length of time. Obviously it would be a last chance situation though and only with mother present, any difficult behaviour and they’re both banned again.

Your car, your choice but maybe part of the child's problm is that nobody in her life before has set boundaries and stuck to them.
So for that reason I wouldn't take her. The mum can think what she likes of you. Peronally, after what she did in my hoe I'd have nothing to do with her again anyway.
The 14 yer old sounds like she could do with a nice treat...are you close enough to her to suggest a shopping trip to look at make up, clothes, etc and a non-alcoholic cocktail or some such. I was the eldest of four and my mum's friend used to do this for me - so lovely.