How to word in my will that I don't want estranged parent at my funeral?

None of that is going to make the slightest difference if, as the OP thinks, the invited parent will inevitably tell the unwanted parent, if asked, ‘for a quiet life’.

And I don’t think it’s at all reasonable to put on a relative or friend organising your funeral the responsibility of enforcing a ban on a person attending. Absolutely you can ask them specifically not to communicate the place or time to the unwanted person, but how is it possible to enforce a similar silence on everyone, especially if the other parent will tell them anyway?

You can't, funerals are public. You can request they don't attend but that's all it is. I host funerals (a church) and it's not an uncommon occurrence, thankfully we have a balcony where we can suggest people go if they want to keep a low profile (many a first wife has sat up there) but if they are intent on sitting behind the family we cannot legally stop them ourselves, only the family can reason with them (hopefully they capitulate and sit at the back quietly.

One of my family’s in-laws wrote her wishes for an immediate family only ceremony to exclude unwanted extended family. It was strictly adhered to by her children, so in her case it worked as they weren’t told or invited and there were no problems.

My DF wrote a letter of wishes for his funeral with music and named funeral director, which made it so easy to organise. He just marked an envelope and put it with his file of documents for us to find so no need toci tactthe solicitor, but he trusted us. Would that work OP?

On the will thing.

Wills in nearly every case are an expression of what the deceased wants to do with their assets, or wishes about what should happen to pets/children. Nothing which needs to be addressed as a matter of urgency. When someone dies you don't have to leap into action within 24 hours and start informing bank accounts or Premium Bonds people that they have died. You get the death certificate, start planning the funeral and get around to doing the admin side of it when you can.

I don't think therefore that the will is the right place to express wishes about your funeral. As others have said, it's unreasonable to expect a funeral director to act as a bouncer. Having said that, funeral directors in my personal experience are understanding and adept at handling all sorts of family circumstances and will have come across this sort of thing before. I do think the best option if you are determined that this person should not attend is to speak to a trusted relative and ask them to take care of it.

Firstly, sorry to hear you may die before them. If you feel that strongly about not wanting them there then there must be a big back story and nobody here should be making light of your wish. I would share it with your closest family and friends, the ones who will speak up for you at the time, and inform said person that you did not want them there (you could even give them a signed letter to pass on on your behalf)They will have been told then and would attend with that weight on them.

I think if you would be OK with only certain people attending (assuming they outlive you), that may be a better way of putting it. You cannot guarantee someone else will turn up, but I am with you about not wanting someone to attend.

You would hope sense would prevail (as for example Nicola Sturgeon not attending Alex Salmond's memorial service), though not guaranteed.

Prepay and arrange your funeral.
Let your next of kin know all the details - especially who the undertakers will be etc.
Have a guest list. Make it a private funeral.
You can choose the songs and the burial details and who will organise the wake - with a guest list firmly in their hands.

I can't see how this would not work.
You can also put your reasonings in your actual Will.

Yep a pretty good summary.

Even if you are doing it for the satisfaction of spiting or hurting your estranged parents it's not as if you are going to be around to get that satisfaction either.

Equally others that do attend your funeral might just see you as a vindictive knob trying to inflict hurt even when you are dead.

you can state your wishes but no telling if it will be obeyed, we faced this with late fil who stated a few people including a sibling not to be there but in the end due to things happening later, he wanted and got a direct funeral so not even me and my partner were there cheaper and easier too. all you can do is state something like
at my funeral my wishes would be not to have my parents attending.

Exactly. Funeral directors aren’t security. They can’t be issued with a photo of the person you don’t want and expected to scan all funeral attendees and manhandle someone out bodily if they’ve succeeded in sneaking in.

Your best hope is to give a letter that explains your precise wishes to whoever you want to organise your funeral, explain you don’t want one parent present and ask them not to circulate the time and date to them. But if, as you say, the other parent will tell them if asked, then I don’t see what you can do, other than not have a funeral at all.

Make it clear that the funeral is not to be advertised in papers and online. In my case my soon to be husband or daughter would be in charge and it’s clear. You don’t tell them where or where it is.

Else you order a direct cremation and then you can do what you like - eg named invitees only at the wake or disposal.

But simply no one tells them

Honestly why do you care so much? You'll be dead, you won't know and however you word it there won't be anyone there to police this - anyone can turn up to a funeral. I'd focus your energies elsewhere, maybe some counselling.

If you're buried in a public cemetery, then how would you stop anyone visiting your grave?

Doesn't it put the other attendees in a really tricky spot? You're effectively saying that one or more need to act as bouncer on the day of your funeral.
Sorry, I do sympathise with your predicament though

None of this matters because you’ll be dead. You could have a message engraved on your tomb stone if you want the last laugh, you’re probably not allowed to write ‘fuck off mum’ though.

You can get cremated and then there is no graveside?

The only thing that I think you could do is engage a security firm to run the entry from a guest list - I don’t even know if any would do this however it is worth scoping out.

everyone to wear read and have a party to celebrate her life afterwards and not a wake full of tears and sadness

Seems to be a lot of this kind of thing nowadays. By all means choose the music and reading you want but I think telling people how they are to behave is a bit much. Maybe they won’t feel like partying!

Certainly living up to your user name, aren't you, @UnsympatheticCharacter?

Perhaps it's better not to have a grave if you don't want them visiting it. You can't have a grave policed 24/7, or at all really. Consider cremation and having your ashes scattered or somesuch. Having a physical memorial will mean they can go to it and you can't stop them. You can't control things after you've died, sorry.

You are overthinking this. There is no special form of words. You just say that you don't want this person to attend under any circumstances. That is all you need to say. You can state your reasons if you wish, but that is not essential. And you have to accept that there is no guarantee that your estranged parent won't attend, regardless of anything you write. Whoever organises the funeral (normally the executors of your will) should not invite your estranged parent, but it is unlikely they will be physically prevented from attending if they find out when and where your funeral is taking place and turn up.

Have a direct cremation that way no one attends ,people can organise a wake /celebration of your life etc after?

My biological sperm donor tried to make my sister's funeral completely empty by not telling any of her family and friends when it was. This included her 3 children, they were 16, 11 and 10 at the time. It worked have worked too if I hadn't phoned the funeral home and pretended to be a florist. There is a way you can do it, good luck to you.

They're available as soon as you like if you give them a copy!