And that's just in the last week. This summer the RSPCA has received more calls and inquiries relating to reptiles and amphibians than ever before.

At the end of June, a corn snake that had been missing for six months turned up in Leeds - and in the same month a couple sitting for the first time in their new home had a corn snake fall out of the roof onto their heads.

Snakes and creepy crawlies are trendy

RSPCA spokeswoman Emma Nutbrown said: "We have also had a turtle found trotting down the street in Cambridge."

Stories like Newcastle-upon-Tyne's crocodile amnesty - where reluctant pet owners can hand over their dangerous animals, no questions asked, to volunteer handlers - make for great column inches.

But animal welfare campaigners and enthusiasts say there is an increasing problem of exotic pets being dumped.

In a way similar to pot bellied pigs becoming a fashion accessory in the late 80s, reptiles, amphibians and creepy crawlies from far-flung places are now the thing to be seen with.

"There is a very small, but significant number of reptile owners whose attitude to pet keeping is that they want to have an animal which increases their status with their mates," Chris Newman of Reptilian Magazine told BBC News Online.

"They want pets that are bigger, scarier and harder than their friends' Dobermans or Rottweilers.

"We believe that some reptiles and amphibians can make excellent pets - some really enjoy human contact.

"They don't need a lot of looking after, they don't shed hair, so are great for asthma sufferers, they don't need to be taken for walks."

But he stressed that a great deal of research is required before any prospective reptile owner decides to take an animal home - and Reptilian Magazine is in the process of publishing a free advice leaflet that will be left at all pet shops and dealers.

Reptiles need to be kept at the right temperature

And he said that while Cayman crocodiles do not make good "pets" - they were in his opinion less dangerous than a Rottweiler.

Ms Nutbrown added: "The RSPCA strongly discourages the purchase of exotic animals.

"All too often people take them on without realising that they will grow, often very big indeed, and that they will need specialist care and attention. That their diets are often highly specialised.

"And you have to ask how happy an animal whose natural environment is a jungle or a desert is going to be in a vivarium in somebody's bedroom."

Ms Nutbrown said: "The trouble comes when the terrapin that fit into the palm of someone's hand two years ago is now the size of a dinner plate and they don't know what to do with it.

"So they let it go in a pond at the local beauty spot. Either the terrapin dies because it is not used to the environment - or they flourish to the detriment of the existing ecosystem.

"Snakes are bought when they are 18 inches long, then when they grow to a few feet long, their owners panic and either let them go or try to dump them anonymously at rescue centres."

The growing market for exotic pet ownership isn't all down to irresponsible fashion addiction, however.

Exotic Direct is a specialist insurer, providing policies to cover pet owners for vets' bills, death, theft and loss.

General Manager Paula Bilsby told BBC News Online: "We saw a gap in the market about three years ago, to provide insurance policies for exotic pets.

"We can cover something as large as a whole zoo or private collection, but we do have about 6,000 private owners who have policies with us, for everything from Chilean rose tarantulas to geckos, water dragons and crocodiles.

"There are an awful lot of people out there who enjoy having poisonous or dangerous animals in their homes, and who are willing to provide the correct care and facilities for them."

Statistics collated by the World Conservation Monitoring Centre indicate that 18,000 green iguanas were brought into the UK in 1995.

Iguanas coming of age

The RSPCA says given that half will have died in transport, a rough total of 9,000 green iguanas will now be reaching their third or fourth birthdays - and be passing the 4ft mark.

"We are already seeing the results of people having bought a green iguana in 1995 and 1996, and not being able to cope with them as they reach their full length of 5ft plus.

"Some owners simply dump them - and a distressed green iguana can be a dangerous thing to encounter. They have nasty claws and a nasty bite. They really are not pets.

"What a lot of people also don't realise about iguanas is that they react quite badly to menstruating women - they detect the hormone change and it can prompt them to attack."

Who is going to feed your snake while you are on holiday?

In the meantime a whole menagerie of exotic animals are on the loose - and quite apart from being vulnerable, are a danger to the public.

The Dangerous and Wild Animals Act of 1976 requires anyone who wants to have certain dangerous or poisonous animals on their premises to get a licence.

But it is feared that some owners are not licenced, and feel that they cannot call charities like the RSPCA without being prosecuted.

Lyn Fennessy, regional liaison officer with Reptile Trust, said that the Cayman crocodiles the group believes to be at large in the north east pose a serious threat to public safety.

She said: "When fully grown these creatures reach 6ft, but even at 4ft they are powerful enough to remove a limb, or even kill a child.

"That is why we and the local police decided to hold an amnesty from prosecution so that people can hand over unwanted pets to people who have the expertise to look after them properly."