Passport because of ETA - adult or child?

[YesTHATMum]

Bit of a stupid question I'm sure. Due to the new Brexit ETA rules, we have to get British passports so this is new to me.
If I get my DC15 a British passport, it will still be valid when he's an adult won't it - He'd just have to renew it when he's 20?
DC has never had a British passport before, is it easier to get the first whilst he's still a child, rather than wait until he's 16?
Will it go more smoothly if I renew my (lapsed) passport first or will it not make a difference?

Yes the passport will still be valid when your son is an adult but if he's close to being 16 (I believe it's within 3 weeks of their birthday) then you can apply for an adult passport which will last longer.

The process isn't really easier for a child's passport it just means you have to apply for it rather than as an adult he could apply himself. They generally take the same amount of paperwork and time.

It won't make any difference regarding whether you renew your passport first as they are treated as separate applications.

Thanks. If I apply for it in the three weeks before he turns 16 do I still apply for it as a parent or does he have to do it?

You don't apply as a parent as it's an adult passport so he would complete the application.