Can I be forced to go back on metformin?

Have a conversation with them about it, but if you fear losing your GP over it, accept the prescription - and don’t collect the pills. They don’t come round and shove the things down your neck, after all.

I'm sorry to hear about your health difficulties. Why are you against taking Metformin?

Your GP (and any other HCP for that matter) CANNOT insist you do anything. It’s your body and what happens to your body is YOUR decision. Do you think he is going to actually stand over you to check you’re taking them?
S/he cannot remove you from the practice if you decide not to take a course of care they think is better for you.

I had the same concerns when my GP tried to bully me into taking a statin. I completely refused and gave my reasons. He had to accept that. I am still on his list. Health care professionals are there to advise, they cannot coerce a patient into doing anything against a patient's wishes.

Your body your decision.

I’m with @Guzzler and @wiflib , it’s better to have a conversation with your Dr explaining what has happened these last few months and politely decline the meds, he/she can’t sack you! Your HbA1c is weighted towards the last few weeks so may not be as bad as you fear anyway.

I know it's easy to say 'just say no' but for some people that is hard to do and they feel intimidated. It might seem good advice to just take the prescription and not take the tablets but I think that that leads to more stress, ie, you get the prescription from the chemist (because the Doc will know if you don't), you then have to remember when that prescription would have run out had you been taking the tablets) and then get another prescription (or as already mentioned you don't get the prescription and then you are back to square one at your next appointment). You then go back for your blood tests which may still show a high h1ac and your Doctor will wonder why and maybe up your metformin or start talking about insulin because the metformin you haven't been taking isn't working. It all sounds very complicated and deceitful to me and would add to the stress. I would not lie to the Doctor about what medication I'm (not) taking, it can skew his/her following actions. I would have a conversation with him, listen to him and all the rest and then say 'Well I want three months without it and then we can re assess', that is perfectly reasonable. As others have said, it is your choice and I think the only reason Drs would chuck someone out the practice is if they were abusive or putting themselves in immediate danger by refusing medicine or being massively reckless.