Animal importers have exploited stripped-back border checks to bring unmicrochipped dogs and heavily pregnant mothers into the country.
Experts told the Commons this week they have seen a boom in dog sales, with many new owners willing to take on a pet as they work from home.
Criminals see the puppy trade — valued at more than £500 million a year — as an “attractive option” than can be easily adapted to expose import loopholes and a lack of enforcement.
Paula Boyden, veterinary director for the Dog’s Trust, told the environment, food and rural affairs committee that legal importation of puppies “decreased significantly” in the first pandemic lockdown, but the number of health certificate registrations for new pets this year has “sky-rocketed”.
She said: “We know there has been a significant increase in individuals buying dogs. Importers are very good at adapting, they know the right times to come into the country and where they are not going to be challenged.
“There were no checks in the early period of lockdown because of Covid restrictions.” Illegal puppy traders have been renting homes in affluent areas to “pass a puppy off as UK-born”, she said, using pandemic restrictions to avoid awkward questions.
Data released in August identified dachshunds, English bulldogs, French bulldogs and chow chows as breeds whose price had increased during the pandemic, amid fears of a surge in abandoned pets when lockdown ends.
Danielle Dos Santos, senior vice president of the British Veterinary Association, said it was too early to identify the health implications of a pandemic boom in illegal dog imports, but warned that the dangers of unchecked animal arrivals are well-known.
“They pose not only a risk to the individual dog, not only to the UK dog population, but in certain situations a real public health risk as well”, she said.
Dr Jenny Maher, of the University of South Wales, identified a “buoyant illegal trade” through puppy farms which do not have licences or microchipping.
Ms Boyden said they had heard of vets in Lithuania offering to sedate puppies for them to be smuggled in.
The environment minister, Lord Goldsmith, told MPs the Government was considering increasing the minimum age at which dogs can be brought into the UK to six months under a plan to deter puppy smuggling.