Circus owner Bobby Roberts has been convicted of animal abuse after footage emerged of a 58-year-old elephant being beaten with a metal rod in the animal enclosure.

Roberts, 69, was found guilty at Northampton crown court of causing unnecessary suffering to the performing elephant. He was given at three-year conditional discharge and was not ordered to pay costs or banned from keeping animals.

The charges related to animal cruelty by an employee, Nicolai Nitu, who has since left the country.

Roberts' wife Moira, 75, was found not guilty of the same charges.

A film, secretly recorded by Animal Defenders International between 21 January and 15 Feburary, 2011, shows Anne the elephant being hit with a pitchfork by Nitu. He is seen hitting and kicking the animal several times in the enclosure in Polebrook, Northamptonshire.

Roberts said he would not have condoned the behaviour of Nitu had he been aware of it.

After the abuse footage emerged, the animal was retired from the circus to Longleat Safari Park. Roberts also gave up a camel named Monty, making the Bobby Roberts' Super Circus free of wild animals, even though ponies and horses remain.

Since her retirement, Anne has received veterinary attention and her health has improved.

Following the trial, Clair Howell, defending Roberts, said: "He's a broken man. This case has ruined him, his reputation and his life."

Throughout the case, Roberts had denied the allegations, saying he did not know the abuse took place.

Speaking about Nitu's abusive behaviour, he said: "It's disgraceful, disgusting. I can't tell you what I would have done [if I had found out]. The police would have been involved. Still now when I think about it, it goes through me, I just can't believe it."

Despite the conviction, ADI spokeswoman Jan Creamen said the sentence was not sufficient. She said: "Despite the considerable suffering caused to Anne the elephant, the sentencing meted out to Mr Roberts is derisory and provides no faith that the Animal Welfare Act can protect animals in circuses."

ADI said Anne's story is just one of many, and that they are calling for the government to prohibit the use of wild animals in circuses.