well in any contract you're bound by your signature (L'estrange princilpe), including all those terms and conditions found herein, no matter if its in small print or printed on a standard form.
You would be able to rescind the contract if you can prove a genuine and honest mistake, or you were under duress or you can prove that it is not my deed i.e not your signature.
You could also claim that you have been misrepresented but it can be quite tricky esp. when the employer has relied on your undertaking and has embarked in performing their side of the contract.
It can be even trickier if the employer has a legal dept advising them. But there are ways...