Pooches in pouches are all the rave

Paris Hilton, Nicole Richie and the neurotic Tinkerbelle

The inexorable rise of the designer doggy bag, with the likes of Geri Halliwell, Paris Hilton and Jessica Simpson constantly toting their shih tzus and malti-poos in monogrammed pet-carriers, has reached critical mass.

Gala openings have become haute-couture versions of dog shows, and welfare charities and animal behaviourists warn of the long-term physical and psychological effects of all this canine cosseting.

"It's clear that these bags are nothing more than papoose substitutes for the childless," says Matthew Morris of the Blue Ribbon Dog Company, a pet-accessories emporium in New York.

"These dogs are treated like eternal babies, which is kind of unhealthy, both for the dogs' development and definitely for their owners'."

Case for the prosecution: Paris Hilton. She recently defended the behaviour of her "little princess", a chihuahua named Tinkerbelle, after she bit the hand of a passing TV producer.

"She is highly strung and very neurotic," she conceded, as Tinkerbelle's imperious head peered from the rim of its Louis Vuitton sac de chien.

"But she's prepared me to take on the role of a mother in all kinds of ways."

Geri Halliwell's shih tzu, the long-suffering Harry, has bobbed along at, or just behind, the shoulder of his mistress for the past five years. "I tell him everything," Halliwell has said, dreamily.

"He's my confidant and best friend. He understands me better than anyone else."

Daisy, Jessica Simpson's malti-poo, is, she gushes, "my darling girl. I phone Paris and we swap notes about our sweethearts' little ways and habits like hysterical moms".

Uma Thurman probably won't be a calendar pin-up after she was recently spotted in New York carrying her dog in a see-through holdall - that appeared to be sealed - flung over her shoulder.

The doggy bag has made sporadic appearances in history. The actress Tallulah Bankhead, born in 1902, used to transport Deloras, her maltese poodle, in a crocodile-skin shoulder-bag (she also set fire to the unfortunate creature by absent-mindedly flicking cigarette ash on her).

But doggy bags really gained momentum about six years ago, in New York, when Madison Avenue ladies were seen arriving for lunch with their impeccably groomed affenpinschers or pomeranians secreted in specially adapted bags.

Then Reese Witherspoon was seen transporting her chihuahua in a PuchiBag Designer Dog Carrier in Legally Blonde.

"Things went ballistic after that," says Morris. "It became a craze, with the dog having to match the bag, or vice versa. Dogs had suddenly transcended their animal status and become the ultimate accessory.

"I think that sometimes people forget that they're living things. I guess those real high-end toy dogs had become too precious to be subjected to messy things like sidewalks, lamp-posts, or other, dirtier dogs." Original doggy bags were ill thought-out. "They hung at an odd angle, causing discomfort to the dog inside."

Morris designed the kidney-shaped K9 Sport Travel Case, trying to minimise the damage. "I thought I'd at least ensure an even ride for poor Fido," he says.

Houses such as Gucci, Burberry and Louis Vuitton have waiting-lists for their own doggy bags.

"We introduced ours three years ago, and it was an instant bestseller," says a spokesperson for Gucci, where dog-owners have to wait three months for their bags.

What are the likely long-term effects for dogs who've swapped walkies for ridies?

"This practice could become distressing to dogs," says Julie Stainton of the RSPCA in Britain.

"Celebrities are role models for young fans and should demonstrate responsible pet ownership. Dogs should be walked and not carried everywhere, in order to keep limbs strong and healthy, and they should never be treated as a fashion accessory. In addition, exposing pets to the media throng and flash photography can be distressing.

But Halliwell is having none of it. "Harry likes the limelight more than I do," she protests.

"He loves it when there are people and cameras around. He's a real ham. And he's always running around when we're at home.

"I think he'd be lost if I didn't carry him everywhere with me."

- INDEPENDENT