Self Employment Liability Insurance

ok im a plumber working for a small company and in recent weeks I have been dismissed because of lack of work. I go to college to get my city and Guilds certificates even if I import my plumbing is designed to happen to my essence. My boss asked me last week to go self-employed and subcontract to him. He said as soon as work picks up it will take me back to the custom, but I get funded to do my college course unless im working full time so I had to pay 800 pounds (which I do have!) Until the IM back to work full time and recover the money.

I could easily sell my car to get a van and I already have the tools, if I am independent, I would be subcontracted to companies like im only 18 I'd rather not go alone until I few more years under my belt!
So, if my boss didn't have a job for me I could not find work on a site easily.

All I had liability insurance, and to register as self ????? I also used the right someone who can do my accounts

Can anyone give me help if it is a good idea or bad idea??

Thank you.

Your boss can not simply decide that you are self-employed if the terms of your relationship with him have not changed. It's just a way for him to avoid paying NI hloiday pay, sick pay and redundancy payments and not have to make sure. HMRC can only decide whether or not you are self employed and I would see the decision on their part to your employer that they are happy with this arrangement.