I started working for a firm 4 years ago, my interview was brief over a coffee, I was not asked any questions other than when can I start. There has never been a problem with my work . Now, out of the blue, I am being asked for my qualifications and told that I might be getting stood down from my position of fitter. Can I be sacked? Does anyone have any advice?
You didn't say which country you are in. If you were for example a fitter who fits gas pipes in Germany or in the UK, your employer would be in deep trouble for ever hiring you without checking your qualifications, and would have to stop you from working immediately - which doesn't mean they can fire you, they would most likely have to find you different work in the company.
In other positions and/or other countries it's different. Think about where this problem comes from. Most likely the company hired someone new in HR who is checking all the documentation, and that person sees you do not have any qualifications. I assume your direct manager or supervisor is absolutely happy with the work you are doing, or you wouldn't have been there after 4 years. So I recommend you find who in the company wants you to be there and talk to them.
And in most places "four years proven good work experience" is much more important than any qualifications, unless there are legal reasons why you must have qualifications. I'm quite sure your supervisor wouldn't be happy swapping someone with four years doing good work and no qualifications for someone with fresh qualifications who has no idea to do the job. So find out who is on your side, and let them fight your case. If your direct supervisor isn't interested, go to the one above him. And having no qualifications doesn't mean you can't get them, so try to find out what you would have to do to get any papers they might ask for.
I assume by 'fitter' you mean a boiler or pipe fitter, and depending on which country you're from, you most certainly can be reduced in position and most certainly title.
Fitters are generally a certified journeyman who did the entire apprenticeship and one can only be titled as such when having such a certificate, or being certified.
Many companies are mandated, or legally required to only allow titled workers do titled jobs, regardless of skills of the worker.
Handworking trades suffer or succeed (depending on ones view) because of this...a talanted worker cannot do a job one has already been doing for 4 years, because they don't have a stamped piece of paper...on the other hand, people who spent four years in the program can't get jobs, because untitled workers took their positions (for probably less money)
Infact, trades exist at all simply to stop talented but nontitled workers from taking jobs away from titled ones (and often to stop the ever falling wages when this gets abused)
So depending on your region, company, unions, general work politics and or legal requirements, you can certainly lose your title and position, and or be 'sacked' for not having them, but having potentially 'lied' to your employer that you did. (though, this is unlikely, it wouldn't be the first time an employer would have done this to cover their own ass for not doing the check to begin with)
SO if this is the case, you're in troubling times if your company requires you to have papers.
My suggestion would be to plead with them, that you'll start the next apprenticeship at the local college if they'll keep you onboard, and get your papers.