I used to be absolutely fierce about this, partly because the families I saw taking termtime holidays were fully taking the piss (two weeks all-inclusive with the children in club, every year, right in the middle of a half-term to miss new core topics being taught). I will also never forget having to deal with the parent who was furious we wouldn't rearrange her daughter's A Level exams around their holiday to Portugal.

Then pandemic. 

Having our children learning at home taught me huge amounts about what a school day actually looks like and how learning happens. My children were starting topics on a Monday and consolidating through the week. The first week of each six-ish-week cycle had more new stuff in it than the last week. What would be an hour's work in a busy classroom can take ten minutes if the child gets the topic. 

So if you take your child out of school a few days before the official end of term, they will almost certainly not be missing any new material. They'll miss revision and videos and sports days, all of which are important in their own right, but they won't miss How To Multiply Fractions. 

If you bring your child back to school late after the holidays ... that's a lot worse. They miss important socialising stuff and new material. And it would be sad for a child to miss the last day at primary school, etc. 

Since lockdown we've taken our children out of school twice for a week each time. First time was for a "once in a lifetime" holiday that was too long for the two-week Easter break and would have been too hot over the summer holidays, so we took them out early – officially it was unauthorised but the school staff were perfectly happy and they didn't miss anything that needed catching up. Second time was when the primary and secondary holidays weren't at the same time and spouse took them to see family living abroad. We didn't get fined either time – this may vary by local authority.

I will still side eye people who totally ignore term dates so they can take their children on holiday and then ignore them (go alone! get someone else to look after the children so they don't miss any school!) and particularly where their children are already struggling at school. 

But taking a few days at the end of term to halve your flight costs? Go ahead.