A Labrador puppy was the first to be handed into a rehoming centre this festive season.
Theo, a 10-week-old pup, was handed in on Christmas Day to the West Calder Rehoming Centre in West Lothian, Scotland, the Dogs Trust said.
Trust bosses say it is 'unusual' for a dog to be handed in on Christmas Day itself.
'It is tragic that dogs are still being bought as Christmas gifts then abandoned so quickly,' said Susan Tonner, rehoming centre manager at Dogs Trust, West Calder.
Theo, the 10-week old Labrador, was handed in to a dog home in Scotland on Christmas Day as an unwanted pet
'People give such little thought to the time and effort that is needed in looking after a dog.
'Puppies in particular are very time consuming and need a lot of attention in their first few months.'
The Trust says Theo's owners had bought him as a present to themselves but could not look after him.
As he is so young, members of the centre staff will take him home with them over the Christmas period so he doesn't get too scared.
Thirty years on from the birth of its famous 'A dog is for life, not just for Christmas' message, the Trust fears the message is failing to get through.
'Christmas is the worst possible environment into which to bring a new animal,' Ms Tonner added.
'New pets need a gentle introduction to the family, to be allowed peace and quiet, and gentle handling.'
The charity's 17 rehoming centres will stop rehoming dogs until Friday January 2 in England, Wales and Northern Ireland to prevent people buying dogs as Christmas presents. This will apply until January 3 in Scotland.
People will still be able to visit the centres and reserve a dog, but will not be able to take their new pet home until the New Year.
Is this the saddest dog in Britain? Theo, the puppy dumped at a rehoming centre on Christmas Day | Mail Online