LONDON (Reuters) - A quarter of dogs competing in the world’s biggest dog show are overweight, scientists said on Monday.

An analysis of canines at Britain's Crufts show - held annually since the reign of Queen Victoria - found 74 percent were in ideal condition but 26 percent were overweight.

None of the animals studied were underweight, researchers from the University of Liverpool reported in the journal Veterinary Record.

The team reached their conclusions after studying 1,000 images of 28 dog breeds placed between first and fifth in their class during competitions from 2001 to 2013.

The issue was most pronounced in certain breeds, with 80 percent of pugs, 68 percent of Basset hounds and 63 percent of Labradors proving excessively fat.

While obesity at Crufts is still less common than in the general pet population, researcher Alex German said the proportion of overweight animals was a concern because show dogs were assumed to be perfect specimens of their breed.

Obesity causes significant health problems in dogs, including arthritis and diabetes.

(Reporting by Ben Hirschler; editing by Andrew Roche)