Special Branch officers are investigating a string of threatening phone calls to a York riding stable owner, after she agreed to host a controversial animal circus.

Lorna Marchi said she would not be intimidated by animal rights "terrorists" who, she says, have plagued her with intimidating phone calls over the past week.

She has leased part of her Wigginton Road stables to The Great British Circus, which will tomorrow begin a fortnight of shows featuring 30 animals, including big cats, camels, llamas and horses.

Circus owner Martin Lacey, who has been working with animals for 44 years, said he too had been hounded by protesters since 1976, but he would not be deterred by threats.

Mrs Marchi, who has run the stables for 15 years, said protesters had attempted to block traffic during the last visit of the touring circus three years ago.

She would not say what the nature of the threats was, but she did confirm they were not death threats.

She said: "These people want to force others to share their views, but we live in a democracy and we do not deserve to be harassed, it's akin to terrorism.

"Frequently, none of these people know or work with animals, but I've dedicated my life to animals, and if I don't have a problem with it neither should they."

Mr Lacey claimed activists pretending to RSPCA workers have been removing promotional posters and leaflets for the circus from shop windows.

He said: "We are the only educational circus in the country and people vote with their feet. We are talking about a circus of a very high standard that has recently won awards.

"Where did this cruel circus lie come from? It's the biggest myth since the tooth fairy and Father Christmas."

Craig Redmond, of the Captive Animals Protection Society, said representatives would attend the circus tomorrow to try to persuade York residents to boycott the show.

He said his group were peaceful campaigners who had no links with militant animal groups. He said the Government was considering the future of animal circuses under the new Animal Welfare Bill.

A York Police spokesman confirmed that details of the threatening phone calls had been passed on to Special Branch. He said inquiries were ongoing.

Updated: 10:47 Monday, March 22, 2004