Have you submitted the resignation?

How long is your notice? What exactly are the requirements? Is this plan something that came out of a regular evaluation process everyone goes through or did they specifically target you after you resigned? Could they be setting you up for failing to meet the requirements so you miss out on some kind of severance pay or make you not eligible for unemployment benefits? Do you need to somehow “sign off” on doing this plan? (what happens if you just don’t?)

They may be trying to tell you something. Is there a history?

If they put you on the PIP and then fires you when you are resigning, SCORE! You can argue for a severance package.

If you have a long notice period and you suspect the PIP is a means to get rid of you earlier, it may well be worth trying to negotiate a reduction in notice period instead. They save on wages and the bureaucracy of a PIP, you don't get a firing on your resume, your new employer potentially gets you earlier - could be a win for everyone.

I have previously been on a personal improvement plan. This was due to the company's inadequate training. Which passed. I raised issues of bullying. this was resolved. Buas I wasn't enjoying my work so I decided to leave. Found a job hand my notice then had a date for exit interview 2 months after I left the business. 2 days after my resignation I was called to a meeting which I thought it was about me leaving the company but it wasn't it was to put me on a Personal improvement plan? Why can they do this? up and coming holidays booked and approved. I will only be working for the company 7

Yes I have resigned

I was placed in the Personal improvement plan after my resignation.

Do I have to acknowledge and sign the Personal improvement plan?

A PIP should say "we need you to remedy <x> by date <y> in order to continue here". If you only have seven days left then either the PIP is moot (date <y> is after you've left), deliberately unachievable, or contains other nasty clauses. The fact that you mention bullying in the past makes it more likely they're setting you up to fail. You don't have to sign; the consequence of not signing is that you get fired, but be extra careful that you understand what you're signing if you do.

... or, in the words of Admiral Ackbar, "it's a trap"

Please add a country/state tag. In some legislations this is indeed illegal and can be construed as constructive dismissal.

@Nelson Being fired for cause typically dies not get you severance package.

@GregoryCurrie It does if you can show that the "cause" was specious.

You say "upcoming holidays are booked and approved". Is there something that prevents you taking those holidays because you are on a PIP?

I would speak with an employment lawyer before doing anything. The only reason I can think of for them to do this is that they want to fire you rather than allow you to resign. Even if you're in an at-will jurisdiction where termination without cause isn't illegal, termination for wrongful cause may well be.

Hi thank you for your comments. Country is UK. I work for private medical virtual company

Even though the holidays are briefly mentioned as if they were a minor issue I would be careful about that. In some countries if you are in the notice period previous holidays request must be confirmed or they become void. In some European countries this is explicitly mentioned in the labour legislation.