Exit interview: negotiating severance

[C33]

I thought I was doing a great job until I saw a mail from my boss indicating he wasn't sure I would make it.

A meeting has to take place on Monday to talk about my performance ( I've just completed my 3 months probation) - I asked my boss about my performance 10 days ago: He said he was satisfied and underlined a point where I had to improve, on which I worked very hard since then.

All of this is known to me because I discovered an email my boss forgot to delete, so they think I'm unaware of this.

I have been asked on a regular basis to do things that are against company policy - big time - I have been asked to approve billion dollars worth of deals in our system - to save time for my boss, and I want to know how I can parlay this into a few months of severance.

I have no idea why they would want to get rid of me, except I have benefits and am on a pension plan and costing them money. If they re-hire someone on a one year fixed contract now, they won't have to pay a pension. Also, I was a maternity leave cover, and they thought the woman I am covering for wouldn't come back, but it looks like she will, so maybe that's what the issue is.

I called an employment lawyer and they said you can't fight wrongful dismissal until you have been employed 1 year. I have to fight this alone. I'm in the U.K, by the way.