Removal in what sense? Are you seeking clarification on why the monarchy should be abolished, or the benefits of imposing exile?

I’m not talking about the benefits.

I’m talking about what legal process is used, and what grounds are given for that process.

It would be done by statute. The only grounds necessary would be that Parliament is sovereign.

Of course, it would need a majority in both Houses, and in practical terms would require popular approval too.

You need "grounds" to remove a monarch?!

What are their grounds for the power they currently wield??

You might need grounds to exile them. At least, you might need grounds for the public to see that as a reasonable step.

> What are their grounds for the power they currently wield??

In this case...Constitutional.

If you are going to do it legally, yes. I presume whoever escorts them out of the palace will want some legal authority to do so.

The grounds for the power they currently wield is that it’s the law.

You definitely need grounds to exile them / strip their wealth.

Taking away their political powers / their status as royals is one thing, but exiling someone is punishment. You can't just hand out punishment for no good reason.

If they commited crimes that were illegal at the time they were commited they should stand trial for that, but I very much doubt any of those are serious enough to warrant exile.