Animal rights protesters disrupted one of Britain’s biggest horse races Saturday when they got onto the course and attempted to attach themselves to one of the fences.

Several protesters could be seen near fence on the the Aintree Racecourse in England’s northwest before the Grand National — the U.K.’s equivalent of the Kentucky Derby — got underway.

The horses were taken back from the parade ring after a announcers told racegoers of the delay.

Around 15 minutes after the race had been scheduled to start at around 5:15 p.m. local time (12:15 p.m. ET), the race got underway and was won by Corach Rambler.

Earlier the day around 50 protesters, holding banners and flags had demonstrated outside the course. Many carried the logo of Animal Rising, an activist group.

Ahead of the event, the group said in social media posts that it intended to “shut down” the race.

“We’re here today to stop harm coming to horses at the Grand National and to really create a conversation about our broken relationship with other animals and nature,” Claudia Penna Rojas, an Animal Rights spokesperson, said in a statement Saturday.

“We need to find ways of loving these animals that doesn’t harm them,” she said.  

Before the start of the race, two people were arrested outside the racecourse on suspicion of conspiracy to cause a public nuisance, the Merseyside Police Force said in a statement.

Another woman, 33, from the London area, was arrested on Saturday in connection with potential coordinated disruption activities at the racecourse, the force said.

“We are aware of some people planning to protest at the event. This has been factored into our plans,” the force said. “We respect the right to peaceful protest and expression of views, but criminal behavior and disorder will not be tolerated and will be dealt with robustly.”

While Aintree Racecourse would not comment on the extent of its security arrangements ahead of the Grand National, a spokesperson said it was working with the police who had a “robust” security plan in place.