A spokesman said the "hugely irresponsible" stunt had scared dogs
A protester was wrestled to the ground after running into the arena at the British dog show Crufts - just as the winner was being announced on live TV.
A Crufts spokesman said the "hugely irresponsible" stunt had "scared the dogs" and put their safety "at risk".
Yvette Short, from Edinburgh, clutched her Best In Show whippet - called Tease - as security guards subdued the protester in Birmingham.
The intruder was carrying a banner bearing the logo of PETA (People for the Ethical Treatment of Animals).
The crowd booed before breaking into applause as he was taken away.
A Crufts spokesperson said: "It appears that protesters from PETA gained unauthorised access to the ring in the main arena at Crufts, and in doing so scared the dogs and put the safety of both dogs and people at risk in a hugely irresponsible way.
"Our main priority at the moment is the wellbeing of the dogs that were in the ring, who are looked after by their owners and show officials."
PETA UK later posted a clip of the incident on Twitter and claimed activists were protesting against extreme breeding and carrying banners which said "Crufts: Canine Eugenics".
It said there were two intruders and named them as members of the Vegan Strike Group, an organisation which claims to fight against animal abuse.