They are famed for battling extreme weather and vicious dogs in the pursuit of providing a first class postal service.
But Royal Mail says its postman have been forced to suspend deliveries during "adverse wet weather conditions" after one slipped on algae and moss on the pavement and broke his shoulder.
A number of businesses have now been told they will not have mail delivered on rainy days after a postman slipped and injured himself on a wet pavement.
Instead, customers in South Parade, Doncaster, South Yorkshire, have been told to collect their post from the town's main sorting office during bad weather.
Royal Mail spokeswoman Morag Turnbull said the safety of staff was paramount.
She said: "Last Friday, a member of staff slipped on algae and moss on the pavement at South Parade due to adverse wet weather and consequently broke his shoulder.
"Following a risk assessment of the area, we have notified Doncaster City Council of the danger posed by the poor condition of the pavement.
"We have explained to customers in South Parade that we must, only during adverse wet weather conditions, suspend deliveries to their address as a precautionary measure until the pavement surfaces are improved by Doncaster City Council.
"Customers will be able to collect their mail from Doncaster Delivery Office.
"We know this is inconvenient and we apologise to customers, but the safety and welfare of our staff is paramount and we only suspend deliveries if the safety of our postmen and women is at risk.
"Royal Mail delivers to almost 29 million addresses across the UK and so it is always a last resort if we decide not to deliver to a specific address or addresses."
Accountant Amanda Henwood, who works on the South Parade, called the move "bizzare." She told the Yorkshire Post: Ã¢â‚¬Å“The thing that really beggars belief is the apparent timetable of events. It took just 24 hours to do a risk assessment and decide we wonÃ¢â‚¬â„¢t get our post when it rains.
Ã¢â‚¬Å“Usually, it takes Royal Mail a month to let us know they are holding an item of mail on which postage has been underpaid, usually by something like 9p.