No.
It's called Cash Accounting, so you only pay/charge Vat on money received in. This method as opposed to the other methods of vat means you won't have to pay the vat man for jobs done when some clients don't pay you for 6 months.
You only pay the Vat man on actual money received into the bank, and it becomes liable from the date you have requested ie 1 December.
It is tricky for a while whilst you keep track of money received from jobs done prior to 1 december and money received from work done after 1 December.