If you're ordering after the 20th December, make sure you select the delivery option called 'UK Courier' at the checkout stage. That means that we'll send it using Royal Mail's Special Delivery service, and it's therefore guaranteed to arrive the next day.
For international customers, deliveries to Western Europe normally take 3 days, and the rest of the world normally takes about 5 days. However we'd recommend ordering as soon as possible since Christmas tends to slow everything down.