I am on probation. I have been since October 2007. The period was extended last month.
I have never been supplied with a contract.
What notice period do I need to give?
One week, until you have been there for 2 years continuously when it goes up.
Your employer is not obliged to give you a contract - it is however obliged to give you written particulars of the job, including salary, hours etc. If it has even failed to do even that, I'm not surprised you are thinking of moving on. Good luck.