There are more than 16 million dogs and cats in the UK; they're our most popular pets, but they come at an eye-watering cost. It's estimated that owners will spend up to £33,000 on a dog during its life and around £24,000 on a cat, but what happens if they get sick and - like millions of us - you don't have pet insurance? Jonathan Maitland investigates what price we're willing to pay for our love affair with pets.