Animal Rising activists were detained on Saturday while attempting to enter the racecourse, thwarting plans to disrupt the Epsom Derby.
A man leaped the fence and sprinted onto the track as spectators eagerly awaited the Betfred Derby, the first significant race of the day.
Police dragged him away and threw him to the ground where he was detained as the crowd booed and some shouted “get him.”
A few minutes later, as police officers raced to stop her, a woman attempted to scale the barrier in front of the Grandstand.
Police pushed her to the ground and detained her just as the horses roared through the finish line, amid the yells of incensed spectators, one of whom shouted, “kick her head in.”
It happened after Surrey Police had earlier on Saturday detained 19 people after receiving information indicating that they were “intent on illegally disrupting” the Derby.
The Jockey Club, which controls Epsom Downs, won the right to enjoin Animal Rising last week, stating that the latter had “explicitly clear” stated its intention to violate security at the racetrack.
A spokeswoman for the organization also promised to “cancel or severely postpone” the event on Friday.
When protesters walked onto the course at the Grand National at Aintree in April, the race was delayed by little over 10 minutes and police had to get them off.
In a statement on their website after the race, Animal Rising said: “After weeks of speculation and discussion, Animal Rising has disrupted the Epsom Derby.
“After the group hit headlines when it disrupted the Grand National at Aintree, once more it is putting the spotlight on our broken relationship with other animals and nature.”
They cited Kerri Waters as saying they chose to act against horses being treated as “objects and property”; they stated that Kerri was one of the disrupters.
Speaking before the race, Superintendent Michael Hodder of Surrey Police said: “We have been clear in our approach that criminal activity will not be tolerated at the Epsom Derby Festival.”