CHRISTMAS is expensive enough without Royal Mail refusing to pop perfectly-ordinary cards through your door unless you cough up an extra �2.30 on top of the postage your friends and relations have already paid.

CHRISTMAS is expensive enough without Royal Mail refusing to pop perfectly-ordinary cards through your door unless you cough up an extra �2.30 on top of the postage your friends and relations have already paid.

Liz and Tom Cornwall were not filled with seasonal goodwill when, on two occasions, their postie dropped Royal Mail missives through their North Walsham letter-box saying they would have to collect, and pay for, cards addressed to them which had insufficient postage

So Tom rifled through documents looking for his passport to prove his identity and trotted down to the collection office in town to pick up the first. But he was having none of it when he saw the offending item - a very modest, 4.5in-square card bearing a second-class stamp and posted in far-distant Waxham, a whole 13 miles away.

Royal Mail wanted �1.15 from Tom to cover 15p 'unpaid' postage and a �1 'handling' charge. He said: 'I told them they must be joking!' The staff member on duty then picked up one of those pretend letter boxes which they use to find out whether your item for posting ranks as a letter, a large letter or a packet. It slipped through the 'letter' slot with no problem and the chap handed it over apologetically with a mumbled explanation about machines sometimes going wrong.

The Cornwalls' second summons was to collect a very standard A5-size card, posted second-class to them by a relative in Aberdeen. Royal Mail again wanted �1.15 from them. Once again the slot device was employed and, once again, their card slipped easily through and another mumbled apology followed.

The same relative had sent identical A5 cards to the Cornwalls' son and daughter, who live in Lincolnshire and Poringland - unfortunately neither of them queried the levy, and each paid up.

'There was no way on earth that card should have cost more,' said Liz. 'Royal Mail must be making an awful lot of money out of overcharging people like this.'

I put their case to Royal Mail and a spokesman responded: "Royal Mail always takes a common-sense approach to the tiny fraction of mail with underpaid postage. Surcharging customers is the last thing Royal Mail wants to do and we would urge people sending mail to ensure they use the correct postage.

'The surcharge that is levied helps to cover the extra cost of handling items that have been underpaid. We always seek to apply any surcharges sensibly as we want to avoid a situation where those who underpay postage end up being effectively subsidised by those customers who pay the correct price. However, if anyone has evidence of being wrongly surcharged they should contact Royal Mail customer services on 08457 740 740. If customers are in any doubt about the correct price of items they should ask at their local Post Office, check online at www.royalmail.com or call our customer helpline."

That's all very well, but doesn't really answer the Cornwalls' main complaints: why are letters which are clearly well within Royal Mail's limits identified as underpaid? How often does it happen - and, crucially, how much money is the company pocketing from customers who don't stand their ground like the Cornwalls?