The use of the animals had been approved by the RSPCA

Organisers decided to take the painted animals back to their farm two days early, but denied it had anything to do with protests by animal welfare campaigners.

The animal art, which began on Thursday, was supposed to run until Monday.

But BBC News Online learned the animals were not on show on Sunday, with a statement at the east London warehouse where the show was being held explaining their absence.

"The severe heat and heavy petting have been causing distress to the animals. It was decided they should be taken back home to the farm this morning.

Show animals

"We apologise for the lack of live entertainment."

The beasts were all show animals from Cheddar, Somerset, used to being on public view, and the paint was animal-friendly, a spokeswoman said.

The exhibition included pigs painted in police colours, sheep painted in concentration camp stripes and a cow covered in images of Andy Warhol's face.

Banksy, from Bristol, real name Robin Banks, has been hailed as "Britain's most celebrated graffiti artist" and designed Blur's latest album cover.

Jamie Oliver was among the celebrities at the launch party on Thursday

An inspector from the RSPCA approved the animals' conditions, the spokeswoman said.

"I think he was a bit dazed by the whole event. But he OK'd it all."

But one woman had taken offence to animals being used as art, and chained herself to railings surrounding a decorated cow.

Debbie Young and two other protesters had demonstrated at what they saw as animal cruelty.

Turf War also included a sculpture of Rodin's The Thinker with a traffic cone on its head and "piles of burnt-out police cars".

The spokeswoman had said the exhibition did not mark Banksy's entrance into mainstream culture.

Corporate requests

Banksy has turned down four requests to do adverts for Nike and his work is usually seen only on walls in cities across the world.