> but I openly fear this is the first step to getting me fired.

It probably is; act accordingly. Continue working if you want, but do no more than your job requires, and only the number of hours per week your country requires without overtime. Find a new job ASAP and contact a lawyer/solicitor.

Just come round to London, tons of programming jobs with great pay.

I'm not sure if lawyering up is so neccessary - the main issue is to be careful in signing anything; if in doubt, or if rushed, then don't sign. If they want to fire you, then you'll end up not working there anyways and the only thing that matters is the conditions and what payment you'll get for your work; and it's quite likely that any offers they make for 'leaving with mutual agreement' will be worse for you financially than them dircetly firing you.

I would just resign, as long as you aren't in a depressed economy, you should be able to get another job. The damage is done to your psych, you can't really be happy there anymore. Only lawyer up if you think you can make some money out of that, otherwise you'll just pile on anguish.

You will not end fired. I suspect he's doing only that so you can resign. So follow people advice and start looking proactively. It's better to leave now, in my opinion, even if they want you still and they never wanted you to resign.