It's the postal equivalent of a reverse charge call.

Now residents in Glasgow's east end are finding that to hear about their local MSP's latest exploits by mail it is proving an expensive business.

In the past fortnight an administrative blunder has led to sections of Margaret Curran's Baillieston constituency receiving cards from Royal Mail telling them they are required to pay a surcharge on a letter awaiting them at the local sorting office, only for them to discover that, upon handing over the required £1.30, the item in question is a newsletter from their MSP about antisocial behaviour.

Labour insists Ms Curran's constituency office has had a single call from a constituent on the matter but refused to provide figures as to how many homes were affected by the glitch.

It is understood the error was confined to constituents living in several streets in the Mount Vernon area, as well as parts of nearby Springboig, and that it occurred because the mailshots had either no or insufficient stamps.

David McDonald, a SNP councillor in the area, said he had been approached by three constituents on the matter and claimed their reactions "ranged from anger to amazement".

One Mount Vernon resident, James Gibson, said when he went to collect his mail from the Shettleston sorting office several other people were there for the same thing.

The 53-year-old said: "When one chap opened it and saw what it was he just threw it in the bin. I'm paying for this woman to send me junk mail I don't want."

Mr Gibson also insisted he contacted Ms Curran's office and was told the matter was nothing to do with them. A Labour spokesman denied Mr Gibson had called.

Last night local MP John Mason, who defeated Ms Curran last summer during the notorious Glasgow East by-election and who will face the MSP again when she gives up her Holyrood seat to fight for the Westminster role, said: "We can laugh off forgetting to put a stamp on something. I'm sure quite a few of us have been there at some stage or other.

But more serious is Margaret Curran's need to send out mailshots on just about anything to try to raise her profile. With the sheer volume of literature she's sending to constituents some errors are going to slip through."

Glasgow's sole Tory MSP, Bill Aitken, said: "Can Labour get anything right? If I were a resident affected I would be distinctly unhappy about paying £1.30 for some diatribe from Margaret Curran.

"She should be paying them to read it."

A Labour spokesperson said: "This is a typical SNP smear story."