Families planning to buy a new puppy for the kids during the summer holidays are being urged to do their homework before rushing off to the pet shop.
The dogs on display may be supplied by puppy traffickers, who are a real problem for the RSPCA as they breed dogs en masse to make money, with little care for their welfare.
Yet an online survey has shown that a quarter of people would still consider buying a puppy from a pet shop, despite widespread understanding that it is important to see the pup with its mother.
Tim Wass, the RSPCA's chief of inspectorate, said: "So many puppies are still supplied by the puppy traffickers, many of whom operate outside of the UK, and produce puppies like a factory production line, with concern only for profit and not for animal welfare.
"We still regularly hear about people who have found themselves with very sick puppies and hefty vet bills just days after they have taken their pet home.
"The latest survey results are a big concern for us and we urge people thinking about getting a puppy to question everything rather than act on impulse by letting their heart rule their head."
The number has risen from 11 per cent of people considering pet shop purchases in the same survey last year, but in direct contrast, 81% of respondents said they felt it was important to know where their puppies had come from.
The RSPCA believes improvements need to be made to how pet shop and breeding licences are issued and enforced in England and Wales.
It hopes to work together with licensing authorities to lower the number of puppies who fall sick or die shortly after being brought home, through diseases such as the potentially fatal canine parvovirus, because imported dogs may not be protected in other countries.
The number of these occurrences seem to be growing. In 2008, pubic watchdog Consumer Direct received 4,627 calls about newly purchased sick dogs, compared to 2,793 in 2006. Since March this year the RSPCA has received almost 500 calls about the puppy trade.
Tim said: "We would like to see minor changes and additions to licence conditions for pet traders to address issues such as traceability, vaccinations and disease control to make them more accountable for the welfare of the puppies they sell.
"The RSPCA is committed to tackling problems associated with the trade in puppies and by working with local authorities we hope to make sure anyone buying a puppy will find the healthy and happy pet they deserve."
The RSPCA's general advice for buying a puppy is to be cautious: do not buy a dog just because you feel sorry for it. If a puppy breeder cannot show you the mother, be suspicious, and if possible see the father too.
Vaccination cards can be easily faked, and if the vet's contact details are not visible or are not located in the UK, there may be a problem with the puppy's background.
For more information visit the RSPCA's website at http://www.rpsca.org.uk/buyingapuppy. If you are concerned about the health or welfare of a puppy, please contact the RSPCA on 0300 1234 999.
Anyone who has already purchased a sick puppy is advised to contact Consumer Direct on 08454 040506 or to go to http://www.consumerdirect.gov.uk.