Campaigners have called for the suspension of hunting activities in Suffolk while police probe leaked footage of an online seminar hosted by the sport’s central organisation.

Opponents want landowners to agree an embargo after the National Trust and Forestry England suspended licences for trail hunting on their land in response to the investigation.

Trail hunting involves the legal practice of following a scent along a pre-determined route to replicate a traditional hunt.

But campaigners have called it a “smokescreen” to allow fox hunting – banned since 2005 – pointing to two leaked training videos hosted by the Hunting Office, which administrates hunting across the UK and said the purpose of its webinars was to discuss legal hunting.

This week, the National Police Chiefs’ Council (NPCC) said an investigation was underway with the Crown Prosecution Service to establish if any criminal offences had been committed.

NPCC lead for fox hunting, Paul Netherton said Devon and Cornwall Police were leading the investigation on behalf of all forces as there were no specific geographical areas to investigate.

The National Trust, which licenses one trail hunt on its land, said it had paused trail hunting and would not be granting new licences for the rest of the season.

Forestry England said it too had suspended all licences for trail hunting in the nation’s forests in response to confirmation that the police were investigating.

Landowner United Utilities also confirmed it had suspended trail hunting on its land.

The Hunting Office said the purpose of the webinars was to facilitate legal hunting and refuted any allegation they were organised for another purpose.

“We will cooperate fully with the police and welcome the opportunity to clarify the situation,” it said, adding that the Forestry Commission’s decision would affect five of some 200 trail hunts operating in England.

A spokesperson for Norfolk and Suffolk Hunt Sabs said: “We welcome the actions of Forestry England, National Trust and United Utilities, and call on all landowners, public or private, to follow suit.

“We believe Hunting is cruel and wrong and should be banned completely without exemptions.

“We hope that all hunts who choose to go out follow the law both in spirit and action.”