The owner of a giant rabbit that mysteriously died in the care of United Airlines claims bungling staff accidentally shut the pet in a freezer and cremated it without her knowledge.

Simon, a three foot long and black-furred bunny was expected to outgrow his enormous father to become the largest rabbit in the world.

The prize animal was alive when he was taken off the plane from London's Heathrow airport but died at a holding facility at Chicago O'Hare Airport.

An airport worker revealed that the pet was placed in frosty temperatures by mistake for up to 16 hours, causing it to freeze to death last Wednesday.

Now, former Playboy model and bunny breeder Annette Edwards said she learned on Friday that her prize animal was cremated without her knowledge or consent.

Simon, a three foot long and black-furred bunny (pictured), was expected to become the largest rabbit in the world. He died after he was flown to Chicago from London last week

Annette Edwards, 65, of Stoulton, Worcestershire, learned on Friday that United had cremated the body without her consent or knowledge. She is pictured with Simon's father Darius, the world's biggest rabbit

Edwards told The Sun: 'The whole thing stinks of a cover-up. I had been asking United over and over again for his body so that I can have him examined here in Britain but they never got back to me.

'Then finally, late on Friday, they called and told me he had been cremated and there was nothing they could do.

'I suspected he was dropped but to find out he was frozen to death has really knocked me. I had asked for the CCTV but they wouldn’t give me it and now I know why.'

Earlier in the week, it was revealed that United Airlines staff allegedly locked away the animal for up to 16 hours in a freezer, where temperature dipped into frigid conditions.

Edwards said a vet had checked Simon shortly before he was placed on the United flight on Wednesday last week and he 'was fit as a fiddle'.

Former Playboy model and bunny breeder Edwards (pictured) claims Simon was 'fit as a fiddle' and was in perfect health when he was checked by a vet three hours before his flight

An unnamed source told The Sun: 'The rabbit arrived fine but there was some sort of mistake and he was locked inside a freezer overnight.

'Everyone thought he was just having a nap or something. Nobody realized it needed to be taken out.'

A United spokesman denied the claims, saying: 'That assertion is completely false. Simon was cared for at the PetSafe kennel facility which is kept at room temperature (on average 70F).

'He arrived at Chicago O’Hare airport in apparent good condition at 10:25 am (local time). He was seen by a representative of the kennel facility moving about within his crate about 11:00am.

'Shortly thereafter, a kennel representative noticed Simon was motionless and determined that he passed away.'

The incident is the latest embarrassment to hit United after it sparked global outcry when a passenger was dragged off an overbooked plane earlier this month.

United said the rabbit was moving around in his crate and appeared healthy when taken off the plane in Chicago, waiting to be put on another flight to Kansas City.

The incident comes just weeks after the besieged airline hit the headlines when a doctor was dragged off a plane by stewards at Chicago O'Hare Airport

About half an hour later, at the company-run pet facility, Simon seemed to be asleep.

Shortly after that, a pet facility employee opened the cage and found the rabbit dead. The spokesman said the airline was reviewing its handling of the animal.

'We won't know the cause of death, because we offered to perform a necropsy free of charge - that's standard procedure - but the customer didn't want us to perform a necropsy, and we understand,' he said.

The spokesman added that the airline offered compensation to the breeder but would not disclose the amount.

Bryan Bergdale, a farmland investment manager, said he bought the rabbit for his boss, who had hoped to show him at the Iowa State Fair.

He had driven from the Des Moines area to Kansas City and was nearing the airport last Thursday when United called with the bad news.

At first, he didn't believe it. 'We'd built a pen and had toys all ready. It's sort of a sad deal,' he said.

Edwards, pictured with Simon's father Darius (right) and his wife Honey. An United staffer said Simon was locked away in an freezer for up to 16 hours

Mr Bergdale, 29, said he had tracked down the breeder and bought the rabbit for his boss, Steve Bruere, who owns a farm real estate company in the Des Moines suburb of Clive.

Mr Bergdale said the rabbit cost $530 and the shipping was $1,800. He said the United representative didn't say anything about compensating him for the loss.

'We're still in the mourning process,' he said. 'We're not quite sure what we're going to do.'

United had the second-highest level of animal deaths and injuries of any US airline last year, or 2.11 per 10,000 animals transported, according to the Department of Transportation.

Only Hawaiian Airlines was worse at 3.99, the result of three deaths among the 7,518 animals it transported.

United transported 109,149 animals last year, second only to Alaska Airlines with 112,281. United reported nine deaths and 14 injuries, the highest figures for each category among US carriers. Alaska reported two deaths and one injury.

United said it works to protect the safety of animals through its PetSafe program, which is staffed 24 hours a day and allows pet owners to track their animals from point of origin to destination.

'Travel can be stressful for animals,' the spokesman said, adding that the carrier has plenty of tips for those who do decide to ship their animals.

Had he lived Simon was expected to outgrow the world's biggest rabbit - his 4ft 4in father Darius.

Simon's new owner is expected to sue because he paid £2,000 for Simon's flight, £85 vet bill and £300 for Simon himself.

United is already working to repair its battered image after a passenger who refused to give up his seat on an overbooked flight was forcibly dragged from a plane at O'Hare Airport.

Airport security officers removed David Dao, a 69-year-old from Kentucky, from the United Express flight. Images of his bloodied face were widely circulated online.

Mr Munoz was widely faulted for his early responses to the situation. He first blamed Dr Dao but later apologized repeatedly for United's handling of the situation.

Two weeks earlier, United was criticized after a gate agent stopped two young girls from boarding a flight because they were wearing leggings.

The airline said leggings violate the dress code of the United Pass program, a benefit for employees and their dependents.

The airline said Mr Munoz would not automatically become chairman of the carrier's parent company, United Continental Holdings, next year as originally planned.