AT this time of year, hearing the clatter of post coming through the letter box is the highlight of many people's day.

Whether it is Christmas presents, cards or the odd bill or two, something we often don't appreciate is the actual process that our mail goes through to reach its destination.

Santa Claus is not the only one delivering Christmas cheer to millions this year - Royal Mail will be bringing the magic of the festive season to all 27 million UK addresses with an estimated mailbag of more than two billion cards, letters and parcels.

Even in the age of e-mail and text messaging, Christmas cards are still extremely popular, with the festive mailbag reaching about 2.1 billion items last year - 50 million more than the previous year.

The average number of cards sent increased from 82 to 86 per household and the number of adults posting 100 or more cards increased from 3.1 per cent to 3.6 per cent.

At the Southampton mail centre, the normal weekly mail is 9.1 million letters and packages. But for the weeks up to Christmas, the staff are bracing themselves for more than 21 million items of post.

Ninian Le Blanc, area manager for Southampton and Portsmouth, said: "Usually the first week of December has a sluggish posting pattern. But mid-December, people and businesses decide that they need to get their post on the way before Christmas.

"In an ideal world we would have a smooth flow of post arriving at the sorting office in Eastleigh for the whole of December but unfortunately it doesn't work that way."

The sorting office at Eastleigh employs 700 staff and covers an area which spreads from Bognor Regis in West Sussex to the outskirts of Bath.

"During the Christmas period, to give us the extra boost we need, we employ 356 supplementary staff who come from all walks of life including pensioners, students and housewives.

"E-mails and text messaging does have an effect on the postal service outside of the Christmas period. Up until these methods of communication became popular, the postal service was growing at four per cent year on year. This year we are at a standstill.

"When people send me electronic Christmas cards on e-mail, I always send them a message back telling them to send it to me again with a stamp on it as they are doing me out of business.

"Traditional Christmas cards are just as popular as people like to have something they can keep and reminisce about. You can't do that with an e-mail.

"At this time of year, posting a Christmas card can say so much. It tells someone that you may normally not have time to get in touch with that you are still thinking of them."

The technology that goes into sorting our post is astonishing. At the sorting office at Eastleigh there are five machines which can sort letters and file them into racks to be taken to their final destination.

"These machines read the postcodes," said Ninian. "These machines can sort 30,000 items of post per hour, whereas a person can sort around 1,500 per hour. They can sort around 50 per cent of all handwritten letters and 95 per cent of typed letters.

"Envelopes that are larger than C5 size or parcels are sorted by hand, but we are working on the technology which would be able to sort these.

"The machines have problems with red envelopes as they cannot read them. At this time of year we see many red envelopes which have to be sorted by hand.

"Each item of post that goes through the machine is scanned and then the address is checked by computer operators. In all, a letter takes about one and a half minutes to go through the machine and be sorted.

"If everyone remembered to put a postcode on their letter, our jobs would be so much easier."

When the post leaves the sorting office it is taking to a postal office in the local area where it is sorted by streets for the postmen and women to deliver.

Ninian added: "At this time of year we have people working 24 hours a day, seven days a week to make sure that all the post is sorted out in time."

So what happens to all the letters they get from children addressed to Santa Claus? Ninian said: "They all go to Lapland, of course, where they are all read by Santa Claus.

"We behave like Santa's elves and send the letters on to him so he can try to fulfil the dreams of all the children."

FACTFILE:

In the four weeks 27 November - 25 December 2002, the festive mailbag is predicted to be 2.1 billion items.

Royal Mail's busiest day this year is likely to be Monday 16 December, with an estimated Christmas postbag of 123 million items - the average daily figure is 81 million items.

Internet shopping is expected to account for more than ten million items.

More than 143,000 postmen and women make Christmas an annual success story with 20,000 additional staff.

Postal workers walk up to ten miles a day delivering the mail.

Royal Mail uses a unique blend of air, road and rail transport to ensure that the Christmas mail is delivered on time - 40 flights a day, around 30,000 vehicles and 33,000 cycles will all play their part.

There are 113,000 letter boxes across the UK.