The Royal Mail has been accused of ripping off home movers as the cost of redirecting post has soared by three quarters over the past five years.
New research by Citizen's Advice shows that since 2012 the cost of having mail redirected to a new address for three months has gone up by 74 per cent from £19.50 to £33.99.
Meanwhile the cost of its year-long redirection facillity increased by 43 per cent from £47 to £66.99 over the period.
The service is designed to reduce the stress of moving home while protecting consumers from identity theft as a result of other people opening their mail.
The cost of mail redirection has risen six times faster than stamps, which have gone up by 12 per cent over the period, the research found.
Citizens Advice said the Royal Mail had a "monopoly" on the redirection service, so consumers have nowhere else to turn if they can’t afford it.
In addition it also estimated that over 150,000 households with different surnames have unfairly paid for two redirections, as Royal Mail treats couples with different names as if they are not living together.
Royal Mail profited £8 million as a result of this last year, Citizens Advice estimates. A spokesman for the Royal Mail said it is planning to ditch its surname policy to make the service "more reflective of society".
Gillian Guy, Chief Executive of Citizens Advice, said: “Many people rely on Royal Mail’s redirection service when they move house to continue receiving important post. “As Royal Mail has a monopoly on this service, people have nowhere else to turn if they can’t afford it.
“We’ve seen Royal Mail continuously raise the price of mail redirection well above inflation and stamp prices. The service should be affordable for everyone. This includes people with different surnames in the same household no longer being penalised - and this change being achieved without a cost to others.”
A spokesman for Royal Mail said: "Redirections remain affordable and offer excellent value for money. For example, at £66.99p a twelve month redirection works out to be 18p a day.
"We note that a recent Citizens Advice report recognised that customers are “very satisfied” with the service they receive, and that the majority of customers who use a Redirection (61 per cent) believe that it is “good” or “very good” value for money with a further 27 per cent believing it is “average” value for money."