Yeah you can, but you'll obviously have to pay for the months that you haven't used.
Here's the paragraph from their
terms and conditions.
8.2 This Agreement may be ended either by you or us giving at least 30 days' notice. You must pay all Charges incurred during the Agreement.
8.3 If this Agreement is ended during the Minimum Period, you must pay the monthly subscription charges up to the end of the Minimum Period. This does not apply if:
(a) we break this Agreement in any way and we do not correct the situation within 7 days of your request;
(b) we go into liquidation or a Receiver is appointed over our assets; or
(b) we increase any of the Charges for the elements of the Service you are using or change this Agreement to your significant disadvantage, provided you give us a minimum of 30 days written notice (and provided you notify us within one month of our telling you about the changes).