Special undercover police officers will mingle with racegoers to prevent protests at the Grand National this weekend.

Animal rights activists burst on to the track last year before the start of the world ’s greatest steeplechase. More than 100 people were arrested and the race was delayed by 14 minutes.

Protest organisers Animal Rising say they have no plans to repeat it. But Merseyside Police are taking no chances and will deploy plain-clothes experts at Aintree to analyse crowd behaviour on Saturday.

Supt Matthew Moscrop said: “These are behavioural detection specialists who identify people whose conduct suggests they are not there to enjoy a day at the races – criminal or antisocial – and prevent it happening. There will be armed officers and officers in plain clothes to make sure this is a safe event.”

Protest organisers Animal Rising say they have no plans to repeat it (
Image:
PA)

Race bosses have reduced the field from 40 to 34 runners, and the run-up to the first fence has been cut by 60 yards to slow horses down.

The start time has also been brought forward by more than an hour. The Jockey Club said last year’s disruption had “absolutely no bearing” on the changes. It added: “We undertake a review after every National, part of our relentless focus on putting the safety of horses and jockeys above all else.”

Last week, Animal Rising’s Nathan McGovern said: “Is disrupting races going to be the most effective way to end horse racing? We think not.” More than 150,000 are expected to attend the three-day festival from Thursday.