CHRISTMAS cards should be sent second class this year as nearly a third of first class items fail to hit delivery targets, the postal watchdog said yesterday.

Postwatch Scotland said first class post suffered disproportionately from the Christmas deluge, making a second-class stamp better value for money.

Over the past two Decembers, fewer than 70% of first class deliveries arrived the next day, against a target of 92.5%. However, more than nine in 10 second class deliveries met their target of arriving within three days.

Postwatch also called for Royal Mail to publish its Christmas performance figures so that customers can make an informed decision about their post.

The advice created an angry spat with Royal Mail, which dismissed it as misleading and unfair on postal workers struggling to cope with about 2.1 billion items sent over Christmas.

Tom Begg, chairman of Postwatch Scotland, said: ''Customers should not only post early but also use second-class stamps right up to the last recommended posting date, which is Saturday, December 18.

''Not only will customers be more likely to get the service they are paying for, but they will also save themselves money.''

Royal Mail defended its Christmas performance, claiming that Postwatch had distorted the fact that first class post still arrives before second class over Christmas.

A spokeswoman said: ''Postwatch has not given the full picture. The figures show that 90.3% of first class mail arrives within two days, before the third day after posting - the target date for delivery of second class mail.

''Our postmen and women do a fantastic job at Christmas delivering the mail for the nation. They work very hard at Christmas - there's only so much mail they can carry or push in a trolley - but despite the volumes, our people give priority to first-class mail.''

Under the terms of its government licence, Royal Mail's performance between December 1 and the end of the New Year bank holiday does not affect its performance targets.

The spokeswoman defended its decision not to publish its performance. ''Royal Mail is not obliged to publish its performance over December.

''But that is for the very good reason that it gives a misleading impression of how well we're doing, considering the increase in workload.''

Last December, only 62.9% of first class post had arrived the next day, compared with 68.9% the previous year.

The November performance also slipped to 80.5% last year, but this was blamed by Postwatch on industrial action which had affected the service.

The watchdog said the daily workload increased over the Christmas period from 82 million items to 135 million.

Extra staff are brought in to tackle the deluge.

John Brown, Scottish regional secretary for the Communication Workers' Union, which represents the postal workers, said that the argument was a ''petty'' attack on Royal Mail.

He said: ''I think Postwatch is being a bit disingenuous. They know we deal with far more mail at this time of year and do our best by hiring additional staff.''