Using umbrella company: employed or self-employed?

[goodssb]

I had a part time job, earning about 1K income at a school. It's supposed to be self-employed because the school paid me gross and I needed to deal with the tax things myself. Therefore I found an umbrella company to deal with it. The umbrella company deducted employer national insurance and income tax and their charge and then paid me net income. They also issue me a payslip.

My questions is, in order to claim this income, will I be treated as self-employed, or employee of the umbrella company? I.e., do I still need to register with the HMRC as self-employed, or the payslips and bank statement will be suffient for this purpose?

Thanks a lot in advance. Any comments welcome.