• Climate and animal rights group Animal Rising, who demonstrated outside Aintree, claimed on social media their actions "aimed to prevent" the death of horses.
• The British Horseracing Authority "robustly condemned" the protests, adding it would analyse the races to understand what caused three horse fatalities over the three-day meet.
Image: /BBC
"Ignorant" protesters are to blame for the death of Hill Sixteen during Saturday's Grand National at Aintree, says the horse's trainer.
The start of the race was delayed by 14 minutes after animal rights activists entered the track.
Trainer Sandy Thomson said the delay "unsettled" everyone.
"It was all caused by these so-called animal lovers who are actually ignorant and have absolutely no idea about the welfare of horses," Thomson said.
Speaking on BBC Radio 4's Today programme, the Scot added: "There were quite a lot of the horses buzzed up."
When asked if he had considered withdrawing Hill Sixteen from the race at that point, he explained: "When they got down to the start, nobody quite knew what was happening.
"The starter wanted to get them off as quickly as possible, then the horses were drawn forward then told to get back.
"One of the other things missing was the parade. I think that gives the horses and the jockeys that couple of minutes to gather their thoughts and that didn't help the situation either."
Climate and animal rights group Animal Rising, who demonstrated outside Aintree, claimed on social media their actions "aimed to prevent" the death of horses.
"We want to offer our deepest condolences to anyone connected to Hill Sixteen or who has been impacted by their death," the group said.
"Horse deaths and injuries are an unavoidable consequence of the way we use animals for sport."
The British Horseracing Authority "robustly condemned" the protests, adding it would analyse the races to understand what caused three horse fatalities over the three-day meet.
Police said they arrested 118 people over Saturday's disruption, which saw nine people enter the course.
Footage appeared to show some protesters making it on to the track and trying to attach themselves to a fence, before being removed by police.
Dozens of others attempted to climb over or glue themselves to security fencing around the track but were led away, with police also confiscating ladders.
Animal Rising said their supporters had entered the track to delay the race.
After the delay was announced on the racecourse public address system, the 39 participating horses were taken back to the pre-parade ring.
The jockeys were asked to re-mount their rides six minutes after the scheduled start time, with the race starting eight minutes later.
Thomson added that Hill Sixteen was "quite used to the fences" at Aintree having previously finished second in the 2021 Becher Chase and seventh in this season's version of the same race.
As well as the death of Hill Sixteen, Dark Raven was put down earlier on Saturday following a fall during the Turners Mersey Novices' Hurdle, while Envoye Special suffered a fatal injury in the Foxhunters' Chase on Thursday.
Two other horses in the Grand National - Recite A Prayer and Cape Gentleman - were treated on course and taken away by horse ambulance for further assessment.
There have been five fatalities from 395 runners in the 10 Grand Nationals raced since safety changes were introduced in 2012.
Thomson said figures "point to the fact" the horses were unsettled by the delay.
"If we look at the last nine years since the course has been modified there's been an average of under two fallers at the first two fences," he said.
"This year everyone got very uptight about it - horses, jockeys - and there were eight fallers at those first two fences.
"We as a sport are continually moving forward, we're continually trying to make the sport safer."
In 2012 changes were made to the Aintree course following a safety review.
This included moving the start 90 yards closer to the first fence to help slow the speed the horses arrive at it. The start has also been moved further away from the crowd to reduce noise that can distract the horses.
Some of the fences were also redesigned, with a reduction of between four and five inches to the drop on the landing of Becher's Brook among the changes.
Changes to the fences' core material were also introduced, with a plastic centre replacing the wooden stakes which traditionally supported the structure of the fences to make them more flexible and less likely to cause dangerous falls when hit by horses.
"The BHA and the Jockey Club are continually in contact with the RSPCA [Royal Society for the Prevention of Cruelty to Animals] and World Horse Welfare," Thomson said.
"If you look back 20 years ago and you look at the fences there has been huge modification."
Earlier this year, changes were made to rules on the use of whips in British racing which reduced the number of times the whip is permitted by one - to seven in jumps races and six in flat races, with jockeys facing suspension for going above that limit and their horse being disqualified if they go four or more over the threshold.