As many people wind down to prepare for the Christmas break, postal workers are working around the clock to make sure all of our cards and presents are delivered on time.

Business Reporter MARK CASCI visited the Royal Mail's sorting office at Forster Square, Bradford, to witness first hand the frantic work which goes into getting our cards from A to B.

For the vast majority of us, Christmas cards magically appear through our letter boxes.

Our involvement is limited to simply buying the stamps, sealing the envelope and slotting it into the post box, with few of us giving a second thought to what goes on after that.

In reality the whole operation is a vastly complicated mixture of good organisation, impressive technology and hard work.

And at no other time of year is the Royal Mail relied upon more than right now.

The amount of work the Forster Square sorting office has to deal with virtually doubles at this time of year, with millions of items of post flying through the building each day.

With packages coming in from and being shipped out to homes across the world, the cavernous sorting room is a frantic hive of activity, with workers toiling around the clock to process all of the mail.

The extra work requires a swelling of staff numbers, with some extra 200 temporary workers brought in each year to cope with the demand December brings.

Throughout the aircraft hanger-like room, a variety of complex machines painstakingly separate all of the mail in seconds according to their classifications.

Martin Brennan, mail centre manager at Bradford, proudly said the sorting office was named as the UK Mail's Best Mail Centre earlier this year.

To demonstrate the first part of the process he tipped in a bag of freshly arrived mail into the first machine, which resembles a large tumble dryer. The mechanism - within just a few seconds - sorts the first class letters from the second class letters, and faces all of the communiqués with the address pointing in the same direction. It also reads each letter's postcode and sorts them accordingly.

The machine can sort up to 30,000 letters an hour, compared to about a 1,000 an hour which can be done manually.

Within two minutes the mail bags have been neatly sorted into piles of letters and cards.

Mr Brennan said: "To give you an idea of how bustling we have been, take into consideration that the machine you've just seen normally stops running at 8.30 at night - it actually ran until 5am today.

"It is starting up at 11.30am today when normally it would begin at 2pm or 3pm."

For mail without postcodes, the work then passes to a small army of manual sorters who painstakingly file each letter into order to make sure it gets to its intended recipient as soon as possible.

This week the traffic of the amount of packages and letters coming through the building is up to 1.4 million a day, an increase of about 500,000 on normal periods.

Despite the frenetic activity, Mr Brennan said lunchtimes were usually a fairly quiet time of day, and that the really busy period comes at about 8pm. It is from here that the mail for not only Bradford but also Halifax and Huddersfield is sorted and huge articulated lorries arrive and leave in their droves with more mail.

Most of the mail is carried via road although some of the country's more remote areas such as the South West and Northern Scotland have their mail flown to them.

While it is often said that letters are dying out in the face of electronic communication methods, it turns out the information superhighway is actually bringing new use to the post service delivery system.

Increasingly large numbers of people are shopping online, meaning huge growths in the amount of parcels, or packets as the postal workers call them, are being sent each year.

Mr Brennan said that packet levels are 21 per cent up on last year and new machinery to separate them like the letters is due to be rolled out in the new year.

Despite the huge strains placed on the 650 staff at the sorting office, the room is full of good cheer with workers smiling and laughing as they work. Many of them wear Santa hats and other Christmas garb.

In all, a card can arrive at the sorting office, be sorted according to its postcode and sent on its way from the building within 90 minutes.

The high levels of technical work and organisation which goes into sorting the mail accurately and getting it delivered so quickly is genuinely impressive to a first time observer.

But as Mr Brennan said: "We have been doing this now for 350 years, we have picked up a thing or two over that time."