From the Orange T's&C's
"2.1 For each Device you own, your Contract starts on the date of Registration and will continue for the Minimum Term and thereafter You have limited rights to terminate your Contract during the Minimum Term as described in Section 4."
"2.2 After the Minimum Term ends, we will continue to supply you with Services as normal until your Contract is terminated in any of the ways described in Section 4."
"4.1 You may terminate your Contract to expire at any time after the Minimum Term by giving us at least one month's notice. You are free to restore your Contract throughout this notice period, should you change your mind."
If you want to read anymore:-
http://www1.orange.co...Services-20110215.pdf