Any mum will know that, when it comes to siblings, there is an order. One arrived on the planet before the other and she knows that.
"I was here first." She doesn't actually say this (much) but it's in the expression on her face.
Imagine the rare treat of sitting in the front seat of a car. H8 will expect the position of privilege.
R6 meanwhile is a much more laid back character but occasionally just to wind up her elder sibling or just because... she will want to sit in the front seat. So she puts forward her case and wins.
H8 refuses to sit in the car at all.
Eventually, after much persuasion (and a bit of shouting) she will condescend to sit in the rear seat behind her younger sibling.
For the entire journey she is plotting R6's downfall. She would rather the car crash than give up her front seat. She kicks the back of the seat in front of her and scowls.
On the occasions H8 is (triumphantly) in the front seat R6 might sulk a bit, but then being much more laid back she sits behind happily pointing out things of interest ("Ponies!") and making observations ("Mummy are you driving too fast?").
Actually they rarely travel in the front seat - only in Grandma's Micra which doesn't have an airbag and usually when there is a there and a back so they can swap. But H8 is very much aware of precedence.
Which is what makes me uncomfortable about the Labour leadership election. It made me uncomfortable all along.
What were they thinking? One brother or the other but not both.
So the younger sibling got into the front seat and not just the front seat, the driving seat. Is David going to sit behind Ed watching him drive? Or will he be sitting there waiting for him to crash?
It might make for some entertaining politics but I can't help thinking that the trades unions have just shot the Labour party in the foot.