The rising cost of postage is fuelling a market in reused stamps, allowing shoppers to buy them online for a quarter of the price.
A first class stamp now costs 67p, but uncancelled ones are available for as little as 16p on sites including eBay.
The Daily Telegraph discovered a booming second-hand market with eBay alone hosting more than 2,100 listings for re-used first and second class stamps.
One seller told the Telegraph they sell 20,000 reused stamps a month, claiming that they had had “no issues to this day” with the stamps they sold.
Another seller said used stamps are largely acquired by exploiting charities that sell on their received envelopes in large quantities as a way to supplement their incomes, usually to stamp collectors.
One worker at a Royal Mail sorting office claimed she sees 100 reused stamps make it through the system everyday as cost-cutting measures have led management to tell staff to turn a blind eye and no longer strike-out stamps by hand or issue penalty notices.
The news comes at a bad time for Royal Mail, which has seen its share price drop by 32 per cent since it issued a profit warning at the beginning of October. It is estimated that the industry could cost Royal Mail as much as £10m a year.
Many of those buying uncancelled stamps are believed to run mail order businesses, a lucrative sector for the Royal Mail as internet retail continues to grow.
In 2009, Royal Mail issued new tamper-proof stamps with security features that included two oval slits either side of the Queen’s head which are supposed to tear if attempts are made to remove the stamp from an envelope, as well as a finely printed overlay of the words ‘Royal Mail’.
Silvia Rook, lead officer for Chartered Trading Standards Institute, said she believed the black market could be due to recent increases in the price of stamps.
“In the past when stamps were just pence, this was not such a big deal. Now stamps are an expensive commodity and if you can pick them up cheaply it does make a difference,” she said.
Stuart Simpson, chief financial officer at Royal Mail, confirmed that the company were considering further rises to the cost of the stamps – which have risen from 36p to 67p for a first-class stamp over the last decade – as a way to offset these losses.
Ofcom this week highlighted a number of causes for concern in its annual report into the economic health of Royal Mail – including a failure to reach a benchmark of five per cent profitability, the level at which the universal service is deemed to be sustainable.
Ms Rook also stressed that the use of uncancelled stamps is illegal as customers are effectively getting a service for which they are not paying full price.
Both the sale and use of uncancelled stamps are illegal under the Fraud Act 2006, however eBay sellers avoid prosecution by adding disclaimers to their listings that state stamps are for collectors only.
When contacted, eBay said they would investigate the listings brought to their attention by The Telegraph.
Royal Mail confirmed it was aware of the online market in uncancelled stamps and said it took any attempt to defraud it ‘extremely seriously’.
“It’s important that we collect all revenues to fund the Universal Service as letter volumes continue to decline. It’s also important that everyone pays their way,” a spokesman said.
“Royal Mail’s priority is to cancel all stamps when a mail item enters the network to reduce the risk of fraud. We also have a range of revenue protection processes in place to identify and stop uncancelled stamps that have been re-used,” he added.