They can hide your contract all they like, you do have one
However, as you have only been there a year, you can be dismissed for any good reason.
Some light reading for you
http://www.direct.gov...termworkers/DG_175138
http://www.direct.gov...Dismissal/DG_10026619
http://www.direct.gov...onditions/DG_10027905
"All employees have an employment contract with their employer, although it might not be in writing. If you don’t have a written employment contract, your contract would have automatically been created when you started to work for your employer."
At the very least, you must written statement of your main employment terms within two months of starting work. If you don;t have one, or it is missing then your employers are not working to the law