However, there's no NHS for animals. If Fido or Puss is hurt in an accident or becomes ill, you are responsible for paying the vet's bill. And that can be very expensive.

What it covers

One insurer cites claims for a cat with skin problems - £553.09, a cat with a fractured pelvis - £1,137.32 and a dog with a serious tumour - £2,977.57. It has been estimated that 40% of the cost of owning a dog goes towards unforeseen vet's bills and that only 12% of the UK's 13m dog owners insure their pets.

In addition to ensuring that vets' bills don't send an owner into financial difficulty, pet insurance can provide other useful cover. For example, if a motorist crashes his car into a wall to avoid running over your dog you could well be covered for the expensive repair to the car - and the wall.

Likewise if your dog bites the postman or worries sheep and you find yourself in court, many policies offer useful legal advice and cover for legal fees. Legal liability for damage to anyone or their property caused by your pet is required by law if your dog is covered by the Dangerous Dogs Act.

Some policies offer to pay for kennels or boarding if you have to go into hospital, which could be a real bonus for an elderly person living on their own. A few top-of-the-range schemes will pay for holiday cancellation if your pet is sick or injured.

Most will pay for costs for advertising and a reward if your animal is lost, to varying degrees. Some will pay the purchase price of your pet if it dies or is stolen. One or two will even pay out if you need to take your unruly pet to an animal behaviourist.

Pet insurance is to cover you for the unexpected so vaccinations, boosters, wormers, nail clipping, spaying and neutering won't be covered.

What it costs

There is a wide range of pet insurance providers and polices can differ widely. Decide what level of cover you need and what you can afford. The excess on your policy can range from £25 to £65. For some people it may be worth paying a higher excess and a lower premium - for others it may be the other way round.

Dogs cost more than cats to insure, and you sometimes pay extra for pedigree and bigger dogs. More delicate breeds may cost more to insure with some companies. Premiums may vary according to where you live because vets' bills tend to be higher in cities. Sometimes premiums rise as the pet gets older.

Many companies won't let you take out new cover for over a certain age, such as eight for dogs or ten for cats. Also some firms will not begin cover until the animal is six or eight weeks old. Other companies have no age limit.

Some insurers will have a maximum figure they are prepared to pay out in a year, others will pay out a maximum per claim for illness or accident. It could make a big difference.