A miniature poodle coloured with blue dye gets it\'s backside trimmed at a dog grooming show in a Bangkok shopping mall February 24, 2001. Dozens of owners of small dogs gathered to show off their pet grooming talents with a panel of judges and shopping crowds voting for the fluffiest pooches and most creative decorative concepts. REUTERS/Jason Reed

London - Tucked away in a fashionably shabby corner of East London, Groom Dog City looks - from the outside - like your average unassuming dog groomer’s.

Anyone opening the glass door is greeted by a chorus of woofs and howls from dogs of all shapes and sizes - from little pugs to a drooling British bulldog. But look closer and there’s something rather peculiar about a few of those pooches.

As Ralph the poodle spins around, there’s a flash of colour: his tail is bright green. Casper, a very vocal bichon frise, has a midnight-blue Mohican running down the middle of his head, while fluffy four-year-old Molly, also a bichon, is shocking-pink from head to tail. Welcome to the newest canine trend to hit the UK: the doggy dye.

Harry Potter actress Emma Watson made headlines when she was spotted leaving this salon with a one-year-old Maltese terrier called Darcy - thought to be her flatmate’s dog - after the pup had been dyed fuchsia.

Not surprisingly, the photos sparked fierce debate among dog lovers, many of whom are highly critical of the practice. The salon has even had abusive emails, branding it cruel.

Some vets have expressed concerns that even if the dye is completely safe, this process alters the way the dog looks and smells to other animals - and that could affect how they interact.

Dr Roger Mugford, a leading animal behaviourist, says: ‘Dogs are intensely visual creatures, and I have no doubt they would be aware of a major colour change, particular green and blue hues which their eyes pick up more.

‘It would likely affect the way other dogs interact with them, too - we know that dogs even interact with other breeds differently due to physical appearance, such as bulldog breeds with their squashed noses.

‘In my opinion, it is a step too far. We should let dogs just be dogs.’

But there’s no denying the growing trend, so I’ve come to the East End to find out why anyone would part with their hard-earned cash to give their mutt a cut and colour.

Dog dyeing is still quite rare in Britain, with only a few salons offering the service, but surprise, surprise, it is a well-established business in the US and Japan.

In the States it is known as ‘creative grooming’ and has spawned competitions. It’s not unheard of to see pooches dyed in rainbow colours or made to look like tigers, pandas and other exotic animals.

Johnny Depp’s rumoured new girlfriend, actress Amber Heard, has been seen carrying a cerise dip-dyed Yorkie, while the girls from reality show Jersey Shore often sport dogs in girlie pink and purple.

So perhaps it was only a matter of time until it came to this country. After all, we already have salons offering doggy mud baths and nail varnish (Victoria Beckham’s bulldog Coco has been known to have a pink pedi).

And here at Groom Dog City, owner Stuart Simons, 38 - a former musical theatre actor who retrained as a dog groomer five years ago - has been offering the service since he opened the salon two years ago.

He heard it was happening abroad, so tracked down dog-friendly vegetable-based dyes, which are made in the US, on the internet. They don’t come cheap - Stuart pays £16 a tub, which means his prices for an entire dog start at £50 (but you can get a Mohican for £20).

He says: ‘You can’t use human dyes on dogs. It wouldn’t be safe and can compromise their immune systems. People complain it’s cruel but there is nothing in the dyes to harm them, and we always do a health check beforehand to make sure they don’t have allergies or skin conditions.’

Even so, Stuart admits it can be miserable for the doggies if they spend too long on the grooming table - so he refuses to do multi-coloured dogs. They have to stand around for hours, which can give them sore legs. So why does Stuart think people put their dogs through the rigmarole of being coloured? ‘If they’re already coming in for a groom, it’s just fun and it makes an individual statement, like getting a tattoo done,’ he says.

And Stuart certainly has no problem practising what he preaches - Molly, the bright pink bichon, is his dog.

‘We get people stopping their cars to see her, and the reaction is always good,’ he says. ‘She looks like a pink teddy bear, so people love her.’

As did Emma Watson - apparently it was Molly that inspired Darcy’s transformation. ‘Emma’s been in here a couple of times, and she was admiring Molly’s colour,’ says Stuart, ‘Darcy is so well behaved and looked great afterwards.’

Pink, as you would expect, is by far the most popular shade. But doggy dye comes in 12 vibrant colours, with fittingly silly names including Monster Green, Vampire Red and Silver Shimmer - which I’m told gives a lovely sheen to black dogs.

So how on Earth do you begin to dye a dog? Well, I’m about to find out. Booked in today is Casper for his third blue Mohican.

He is dropped off by owner Chris Amos, 37, a marketing director from Bloomsbury, London who says that Casper loves the attention he gets after his dye. ‘I think it really suits him, and kids absolutely love it,’ he adds. Chris waves goodbye to Casper, who is whisked away by one of Stuart’s two groomers for a quick shampoo (with specialist hypo-allergenic dog shampoo Double K).

Then when Casper has been showered in a huge bathtub, he is ready to be dyed.

Stuart pulls on latex gloves and opens a gloopy pot of Midnight Blue. Holding a rather puzzled-looked Casper in one hand, he pulls the dye through the pup’s fur.

Against the white of Casper’s coat, it’s pretty shocking to see the depth of the colour. And Stuart admits you can’t always tell how it will come out. ‘It’s not an exact science, so we’ve had blue come out green, and red go pink,’ he says. ‘It depends on the breed too - poodles and bichons are perfect, as their hair doesn’t moult. If you put it on an Akita or Alsatian, it would just fall out in a few days.’

On the right breeds, the colour can last up to eight weeks. That’s a long time to wait if it all goes wrong - though it does fade over time, especially after shampoos.

Stuart doesn’t leave Casper for a moment, and stands holding his head in place for ten minutes.

‘If he shakes his head or throws it back, it could go everywhere,’ he warns. ‘And I want to make sure it won’t go in his eyes.’ Needless to say, I keep my distance.

Once the time is up - the dye is left for between five and 15 minutes, depending on how bright a customer wants their dog to go - Casper gets another rinse and shampoo before being transferred to an enormous blow-dryer.

The final touch is a quick trim to neaten up the edges - and, voila, one bright blue Mohican.

Then it’s back to the floor to play with the other dogs. Casper seems unaware of his edgy fashion statement, and if his friends have noticed, they aren’t letting on.

None of them appears upset about their new styles, it’s true, but I can’t help wondering whether they’d rather scamper around a park with their coat a natural colour. - Daily Mail