A couple have been told to restrain their cat or face having their mail deliveries suspended.
Matthew Sampson was notified by Royal Mail last week of a "potential hazard" at his home in Patchway, near Bristol, which was "affecting deliveries".
According to the Royal Mail, four-year-old Bella is a "threat" to staff and has been putting "fingers at risk of injury".
In the letter, Royal Mail says it has been "experiencing difficulties in delivering mail" to Matthew Sampson's home "because of the actions of a cat".
It said the couple's postman had reported that when he pushes mail through their letterbox, their black and white cat "snatches the mail and puts his fingers at risk of injury".
They have been advised to "restrain their cat at all times" or provide an alternative "safe" post box, or their post would be suspended.
Mr Sampson told the BBC: "We've noticed over the last couple of days that the postman is very hesitant at putting the letters in, and Bella thinks it's a game that he's trying to play.
"I haven't seen her put her paws all the way through but I think it's fair what they're saying - it's just how they've worded the letter.
"As to restraining the cat - I'd no way dare."
A Royal Mail spokeswoman said: "If we feel that there is a risk from a dog, or any other animal, at an individual address, we are committed to working with the customer to agree simple steps to ensure we can continue to deliver the mail safely.
"In this case we have appealed to the owner to keep their pet under control when the postman calls and we have invited the customer to contact the delivery office manager to discuss this in more detail.
"This could be done just by making sure the pet is kept safely away from the letterbox, or by installing a cage inside the letterbox to reduce the risk of fingers being bitten or scratched.
"Our postmen and women also use posting pegs which they use to deliver mail safely to properties where there are animals present."